As I see it, we can have our cake and eat it too...
I think there's pretty good reason for the organization the game had originally, keeping the mission definitions on the server. First, it allowed the developers to work on those files, fixing typos, tweaking balance, and whatever else might be called for in response to live feedback, without needing to send updates to the client for it to work. Such fixes might even have been hot-swappable.
You also never want the client to be sending more than the barest information back to the server -- I/O and state verification should be the limit. Redundancy is already going to make that demanding when you have a lot of roving entities within view (CoH was originally optimized enough to play on dialup, but when roving NPC populations were ramped up in PI and elsewhere, it made dialup users choke, and even higher bandwidth players started experiencing rubber-banding more often in those zones as all those verification packets bottlenecked. A less optimized protocol would have made the game unplayable for even more people.
I also suspect AE missions were so limited in size more because the transfer methods used in updating them were very unstable than because Paragon didn't have storage space; this seemed to be verified by the larger mission files allowed later getting lost in transfer more often than not. Also, when the Paragon Market was created, though it was more reliable I believe it used a separate protocol, or at least a great deal more redundancy -- anyone paying attention would notice that activity in the market used exponentially more bandwidth in both directions than the game.
As for recreating original content and the legality of same, you might be surprised how limited the protections of
parody and other obfuscation tend to be. An example: way back in the '80s Dave Sim did a parody of Marvel's Wolverine in his Cerebus comic-book. Marvel lawyers said "let it go, it's a parody." Then he brought the character back the next issue, and the next. With the fourth issue, Marvel's lawyers said: "now you're beyond parody; you're infringing." So ended Wolverine's appearances in the pages of Cerebus.
There's also just the hassle of doing the work. If the community has some obsessive-compulsive lore fans eager to do nothing but recreate what was already there, well... more power to them. But it might have to stay underground and off the radar more that way. I expect that creating new material will prove more attractive: it's easier when you're making it up than when you're trying to accurately copy something else, and less of a
menial task than a
creative endeavor.
All those old stories were the ego-driven creativity of the developers, and many of the characters were even their RP avatars. Who among the player base cares
that much about those characters and stories, if given the opportunity to showcase their own ideas?
