yes, quite. i think this is sort of like what happened with the morrowind mod community, actually. in both instances the ability to make new content isn't simply a matter of making addons and expanding the game. it basicaly lets you make the world dynamic in ways that really cant gracefully be programmed. in addition it allows for a sort of, er, asynchroniouos online play experience if you will
in any case, i think that as far as modding goes, modular, plug-in type mods are definitely the best choice for many things. total conversions aer nice, but they don't have the same flexibility. similarly, the unreal tournament series has mutators, which are basically the same thing -- small, very modular mods. i felt this gave those games a rather sizable leg up as far as custom tailored playing experiences go.
anyway, though, if you wanted an elite game to sell in this day and age, you'd need massive customization. players like showing off. not just how much experience or money or whatever their characters have. if you make an elite like game where the player could customize their ship in infinite ways to make it extremely cool looking (and, of course, powerful. both should go hand in hand, I guess) (and also advertised it, along with this fact) it would probably sell well.