Watching a recent Bringus video on finished but unreleased games for older consoles made me wonder - what games could/should have existed on older machines, but just never made it / weren't ported.
Gauntlet (DS) and Diablo 1 (GBA) come to mind, though the former was leaked.
Doom was famously thought impossible by ID Software to port to the Amiga (but iirc, someone managed to do it just last year).
Any from back in the day you wish could have made it?
I maintain the Wii could have handled some version of GTA, and there's a rumour that it (and FO3!) were in the early stages of development before getting nuked.
Lots of third games:
Mega Man Legends 3
Titanfall 3
Star Wars Battlefront III
Scalebound
And for my own addition, the original version of Silent Hill 3, before Konami executives demanded Team Silent make a bunch of changes to the story, including forcing it to be a sequel of Silent Hill 1.