everything in space is huge
This was inspired by another topic, here, and was originally going to be my response, but I felt that its size and scope warranted a new topic.
Let us first assume that capital ships are quite large, as futuristic materials and construction methods, as well as the mining operations to support them, are advanced enough to produce classes of spacecraft that are not meaningfully limited on the interstellar scale. Within a solar system itself, if there are no mobility requirements and cost is no matter, of course these reasonable size limits are irrelevant, hence Schlock Mercenary-style UNS battleplates are a possibility in-system for defense. Where interstellar movement is concerned and you are trying to attack other systems with many ships, there are limits, but the limits are "high enough" that we can say that capital ships are very large. Hundreds or even thousands of crew, many weapon systems, and many weapon systems large enough to blow many ships out of the analogous water.
Let us also assume that since these large capital ships have the firepower to blow each other up effectively, in the interests of self-preservation of their crews, or at the very least preservation of the cost and materials to build such a spacecraft, or preservation of the mission objectives (bombard a planet after the fight for the sky), any fights between these capital ships will be done at range, with point-defense systems and a screen of smaller ships between them as they lob huge projectiles and missiles at each other. The range at which these combats will occur is such that each ship captain believes he can protect his ship, and get a reasonable chance at taking out the enemy. Yes, he could fly in at full speed towards the enemy and engage at point-blank, but that would be suicide (however it would be an effective tactic if you're losing, a la Return of the Jedi).
I see these large capital or super-capital ships as a way of carving out borders in space, where they would otherwise be meaningless empty space. A capital ship in effect controls a three dimensional field around it. In strategy board game language, a capital ship threatens a set number of squares around it, and thus the enemy may not move through those squares, at least without the capital ship being able to shoot at it. A naval analogy is also apt- capital ships are moveable air-fields and artillery, and do not attack each other in close range, but they do provide control or defense of land and water nearby in range of their guns and planes. Certainly no enemy shipping can occur in such areas.
So, the role of screen vessels becomes apparent, to either extend the range of fire of the capital ship, or protect it from harm. Screen vessels (these are your destroyers and cruisers, and perhaps even smaller vessels) may of course be found outside of a capital group, and packs of these might make daring raids against enemy outposts. But while a part of a capital group, their main concern is with protecting the capital ship, and that goal is accomplished in one of two ways. A defensive role, preventing enemy fire from reaching the capital ship, and offensively attacking the enemy screen, and once that is removed, attack the enemy directly. Being smaller and more numerous, these screen vessels would probably have some specialization. There would be anti-fighter classes, anti-destroyer classes, and anti-cruiser classes. There may even be some that would specialize in attacking enemy capital ships, although these would probably remain in reserve, as the weapons they would carry would be poorly protected, and thus too easily wasted on the front line. If your anti-fighter cruiser is destroyed, you've lost a ship, its crew, and only a bunch of small cheap warheads. If you lose an anti-capital cruiser, you've lost a bunch of large expensive anti-matter pods and a sophisticated delivery system.
The role of fighters becomes much more interesting in this kind of situation. A fighter is the pawn of this space-based chess game. Weak by itself, but with many others (especially when the enemy is low on their own pawns), it becomes very important. Fighters may be able to eliminate incoming large ordinance and serve as an outer line of point defense (think about Vipers in BSG taking out Cylon missiles), and of course they also attack other fighters. Interceptor-type fighters would have small missiles (think of an AIM-9 Sidewinder) or a quick-shooting canon, for which to dog enemy fighters. But fighters aren't just defensive. Strike-type fighters would be able to get through the front lines of the enemy capital's field of fire, deliver powerful explosives against the enemy screening vessels, and attack weak points on the enemy capital ship. They are able to do this through speed, superior maneuverability, and high pay-load capacity.
I've recently begun to think that fighters should be much larger than people generally think. They should be considerably larger than a cargo shuttle, I feel, just because of the technical limitations of the universe. Think about design considerations at Cargo Shuttles, Inc. versus Advanced Fighter Corp.
A cargo shuttle may come in several classes, from a simple puddle-hopper that only needs to take a few passengers or a couple tons of cargo, to a longer-range transport that will move maybe 20 tons of cargo (and unlikely any passengers). Speed is not a major issue, as the distances are short, so a slower, older-style engine will take up less space so that there's more for the cargo. Armament considerations are small, if any, although some hardpoints for extra fuel pods or specialized equipment for maybe scientific purposes might exist.
A fighter though, has completely different needs, and its size is therefore very different. First and foremost, is speed. While the sophisticated tracking systems of the enemy fire control can easily track and put ordinance in front of incoming fighters, if the fighter remains inside the enemy field of fire for a shorter time, it becomes more difficult to shoot down. Maneuverability is the next factor. Changing course quickly causes the firing control computers of the enemy to shoot in the wrong place. Payload is another major sticking point, since there's no point in being fast and agile enough to get within range of the enemy capital ship if you can't hurt it when you get there. The bomb you're dropping or the missile you're shooting is likely many tons in weight. Speed, of course, is requires a good balance between mass and acceleration. High-powered engines, and really over-powered engines, is a must. Plus you need the fuel to hit your afterburners on your way in and out. Rapid changes in your vector is how you survive in the kill zone. So, you can pretty much expect your fighter to be mostly engine and payload. You probably have some thrusters all around your ship to change your direction. Payload increases mass, decreases your velocity, but as I said, there's no point in going in if you can't cause some damage, so strike fighters would be equipped with heavy rockets, bombs, or blasters to get the job done. Again, this just makes the size of your fighter larger. I don't think it's so hard to imagine fighters being much larger than a 747, maybe twice or three times as large. Remember that space is big. Yes, you seem like a bigger target, but the precision needed to hit you when you are a whole planets-width away and traveling at .7c is just crazy. Sure, if you get hit, you're probably dead, unless it was just an interceptor that got you, but if you're good enough, you'll be fine. Nobody said being a fighter pilot was safe, after all.
So, I don't think it's so wrong that fighters are large. I think it's the only thing that makes sense. The real question is, how do we translate this all to a game like EV? The answer of course is, suspension of disbelief.
Yes, the planet on your screen looks tiny compared to your cargo shuttle. Just think of it as "in the distance". It's just background to the epic battles going on in space. The same can be said of capital and screening sized vessels. They however, are shrunk down on purpose. Does it really make sense that a ship as big as an island is only going to have 10 guns on it? Of course not. But we only have 10 guns on it in the game because it makes sense relative to everything else. In "real life" it would have hundreds of cannons of all shapes and sizes, shooting ordinance of every type for every situation. That's the advantage of flying around your own personal star base. But the disadvantage, of course, is that you aren't as fast and much easier for you to get hit. So in essence, capital ships are an abstraction. You get 10 guns because realistically you miss a lot of the time, and you really can't fend off 10 fighters and destroyers buzzing around you. That's why you had your screening vessels and fighters of your own.
I think the solution to scaling in EV is not about making fighters smaller, it's about realizing that larger ships are far larger than you can realistically make them and still have a balanced, playable game. And also realizing that fighters are way bigger than you think they are. Think of it like a logarithmic scale of sorts. As your ships get bigger in the "real world", they don't get as bigger on the screen, nor do their armaments get massively overpowered.
In conclusion, here's how I see the scales of various ships in a realistic universe. These are lengths.
|--------------------------------------------------------------------------------------------------------------------------------------------| capital ship
|---------------------------------------------------------------| escort carrier
|------------------------------| heavy cruiser
|------------------------| light cruiser
|---------------------| heavy freighter
|----------------| destroyer
|----------| light freighter
|------| strike fighter
|----| interceptor
|---| heavy shuttle
|-| light shuttle
Now, for actual graphics, you might want to scale it such that you can pretty much tell how big a ship is by its size, but each ship is mostly on its own scale. Notice that in this example, I have freighters on a slightly different scale (a civilian scale, as it were, since these ships have limited defenses and should be easier to hit anyway), and strike fighters and below are larger on the scale.
|---------------------------------------------------------------| capital ship
|------------------------------------------| escort carrier
|----------------------| heavy cruiser
|------------------| light cruiser
|---------------------| heavy freighter
|----------------| destroyer
|------------| light freighter
|------| strike fighter
|-----| interceptor
|----| heavy shuttle
|--| light shuttle
I feel this is a reasonable relative size for the various ship classes, but of course your mileage may vary, and you may have your own classes, etc. But, using a kind of logarithmic scale, you can create a reasonable difference in size, and require minimal suspension of disbelief. People like seeing details, so let them, make your tiny ships big enough to see. And think about sizes relative to armaments and roles. Nobody's going to build a freighter that can transport so much of a material as to destroy the price of the material when it gets there and floods the market. And nobody's going to pay to maintenance keeping it running for the entire year it takes to mine enough ore to fill it. Similarly, nobody's going to build a fighter so small that it can't deliver a weapon large enough to damage its target in the enemy fleet. Remember that space is big, and in the kinds of actual distances being fought between, you're going to need a fighter with enough speed and fuel to span that distance, so you'll need a much larger engine than in a cargo shuttle. That means a much bigger fighter than you're used to seeing on TV or in the movies, or even on Earth today. An F/A-18 can only fly a bit over 300 miles and it can only reach Mach 1.8. Space is way bigger and combat would be way faster than that, so even with futuristic fuels and engines, you would still expect a space fighter to be much larger, especially if the ordinance you're carrying is going to be much much heavier. Space is HUGE, you can afford to make your smallest craft just as huge if it gets the mission done.