Toolset.

Fast thought after visiting one of the numerous Ubi development studios around the globe:
The only way to create exceptional game is to have exceptional tools.

[We thank you, Cap!]
[Applauds]

Seriously. No good tools? No good AAA game for you, sorry.

And the reason behind is pretty obvious: less time per iteration == more iterations for the same budget. More iterations means greater quality. Greater quality means increased value to your customer and increased sales. Profit.

But there is one trick involved. Interfaces and processes for this tools should be built by UI usability experts, not programmers or artists or anybody else. And the good news is - you can find plenty on IT market. I'm wondering why most of the studios ignore this fact?