Some comments and suggestions:
1. I don't understand the term "beaten" in relation to EV and its plugs. Most good plugs can be played through several times without getting repetitive.
2. Bigger is not necessarily better. Check this site and Ambrosia's page for some good smaller plugs. Examples are Raiders 1.2, Angels of Vengeance, and EV Adventures.
3. Some good larger plugs I don't think you mentioned are Empire, New Horizons, and Bounty.
4. Another way to keep EV interesting is to play as different characters. A well-written plug can usually be played in several different ways. Try to make the choices, fly the ships,and fight the battles in the way that particular type of person would do it. Good generic characters are Trader, Pirate, Mercenary, Bounty Hunter, Rebel, and Confed. Most plugs will suggest a number of other identities as well. Try to play through the plug as each of them. A ho-hum mission in a Reb Cruiser can be really exciting in an Argosy or Clipper.
5. Try strict play. Keep daily backups, of course, but there is still a real sense of loss if you screw up.
6. Try writing a plug yourself. Don't worry about graphics or sounds at first, just try writing a few good missions. It can grow from there.
T.O.P.
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"Good mathematics is not how many answers you know,
but how you behave when you don't know the answer."
The Old Professor Houston, Texas