there's a lot that could be done with it since it isn't completely restricted by hardware limitations anymore. though the saturn emulators it runs on aren't the greatest, so you're probably right... though if a more stable saturn emulator was released that could run an expanded version, that would be nice. i suppose the same could be said of the PSX version. it would be nice to see some new weapons, items, enemies, castle areas added to the original game. maybe add new parts of the map that utilize areas from other CV games? that'd be interesting...
Well, there's also the fact that...
-The saturn version's VDP layers would have to be entirely reprogrammed
-Every single sprite in that game is pre-stretched, meaning that every sprite and hitbox would have to be manually unstretched and fixed to a lower, letterboxed resolution.
-All the new pixel art that was introduced would have to be entirely redrawn due to stretching, and the fact that it all looks very amateur.
If you want as close as the Saturn version as you can get, play it through Yabuse, or play the PSP version. Other than that, re-making the game with a newer engine would be the best option. It would also open up newer possibilities, such as widescreen support, more detailed models, revised bossfights and difficulty level, along with much more.