If the ports are done right, the port data will be stored in Nova Files, leaving the plug-ins folder empty, so you can update old plug-ins as well to go in the plug-ins folder.
The advantage to this is pretty clear, if you simply make the EV/EVO files as plugs for Nova, they would have to overwrite every single resouce in Nova to prevent any overlap (If there's overlap weird things happen, like weird fleets of Nova ships could appear arround Palshife for instance).
Also, lets keep this topic on topic, and not get into pointless debates about which is better or being surprised that somebody got something right...
Chamrin