A game doesn't just "need to be ported to Amiga". It needs to make proper use of the hardware too. I think the problem of most games on Amiga was that they didn't make full use of the hardware. I'd rather play a game with a proprietary idea that suits the Amiga than some laggy crap that is exactly like the original.
Slap Fight... didn't think it was fun to play on C64. But the Amiga had a fair share of excellent shoot'em-ups... Hybris, Battle Squadron, Datastorm... X-Out, I discover now, has more depth when you try stuff out than when I first tried it and just started it and began shooting. And very well programmed.
I'm a fan of Graftgold ever since I visited them, so I wouldn't mind seeing a Gribbly's Day Out. Apparently they were going for the US market on Amiga as well, so all (?) their games were half framerate. GDO should be fully possible at full framerate though
BTW, looking for work. Anyone wanna pay me to code Amiga games? hehe
Would be a sweet job