More Chess Games.
The weakest point of Amiga for me is Chess.
I'm not 100% sure, but there's some Zx-Spectrum games (like Cyrus 2) that could beat any Amiga. I still can play them with ZX-Live.
I didnt tried yet Psion Chess for Atari ST, but I never understood why Chess Games for 68000 are so crap.
Did you ever try Colossal/Colossus Chess? It was pretty good. It was for the AtariST, maybe for the Amiga too. I can't remember exactly.