Iv'e often wondered this as well. I remember AGA games as being tweaked ECS versions, or attempts to copy PC style games.
Now I hanker for updates in the style of games I loved, perhaps higher res, or more effects and colours, and using the HDD as default. Also, I played some NeoGeo shooters with rotaing sprites. I'm sure an 030 could do that, the same with a lot of the fighting games.
so...
A proper fighter for 030 with more than two button support.
A nice RTS with hand drawn artwork, rather than renders (something that looks a bit like the Bitmaps 'Z', perhaps. )
something like 'cybercon 3', but more detailed. with lots of line and filled vectors. I might be weird, but I like plain filled polys. Probably why I love 'rez' on the dreamcast. Actualy, more filled poly games in general. I remember a lot of sims on the A500/A1200 using dithering on a 16colour screen -we could now do away with that, and add more detail into the bargain.
A nice first person RPG, lie EoB or DM. on a nice fat HAM8 screen, with lovely renders done in a modern 3D program. That would look lovely!