What core games, using modern programming techniques, couldn't be made on Gen 6?

Most specifically the Gamecube, since it falls in the middle-power range of the consoles that stuck around. 

I'm not talking about graphically, and lets imagine the Gamecube disks could have their storage expanded. What modern games, if built intelligently (like Xenoblade Chronicles for Wii), couldn't be offered at the Gamcube's power level? I'm not so much asking about the fine-tooth combed physics that cause 'wow' the first time around before becoming old-hat, but rather the core experience.

OBVIOUSLY more power makes new things easier and assists in developing new tricks, but I'm curious what games you guy think could or couldn't be done pretty awesomely on Gamecube level technology.

8 player smash cause not enough ports (or power really)

I... ummm... thats... yeah... o_O

Good question. I suppose that games that recquire a lot of NPCs with decent AI would collapse a 6th gen console after a while

I'm sure  there are tricks for that. Presumably some stuff  from RTS games could help fake it? They tend to have tricks for AI hoards; sorta.

Gta V, and Uncharted/last of us. Sure those last ones it's mostly graphics, but it was impossible for a game in the 6th gen to have such a immersive atmosphere.

Couldn't you play using 4 (8) Ice climbers in Melee?

I'd need to play them before beinig certain but... Metroid Prime was transcendent in its atmosphere so its hard to imagine they COULDN'T be done. 

Also GTA is GTA is GTA, no?

I wouldn't say that:

Loll hmm

Well, I guess if we don't want to go into the whole "technically" part then yea, I guess in a way, you could loll