The N64 expansion pack is a pretty good example. Not all N64 games were playable on old N64s unless you upgraded them.
There really needs to be a certain size to the change. No one was calling the Gameboy Color a part of the 7th (PS2 and Gamecube) generation. That was the gameboy advance.
Again, having exclusive games really isn't enough. The Go as well isn't playable with all PSP 3000 games.








