I don't think I posted here.
I'm not one to talk about higher level play, obviously, but any gameplay of 7/7 I've done (not very much) gives manageable waves, and I'd welcome the extra challenge of higher AIP, because it kinda balances out knowledge acquisitions, a larger empire buffer, more factories and income, and fabricators.
...really, it seems almost like playing 10/10 is a different playstyle entirely, and if it's too restrictive, you can drop the difficulty and actually be able to survive with AI Progress. The problem might be similar to say, Inferno mode in Diablo 3. It's so hard that you are completely pigeonholed into only one or two builds, which ultimately means that the game failed at what it set out to do in the only part of the game that really mattered to people -- the endgame item hunts (but the success of that is a different discussion).
However, I really wouldn't know how to fix that problem without breaking the game. Like, Inferno mode is inherently flawed, and I don't see an actual way to fix it. They piled on a bunch of numbers to the enemies to make them impossible. Likewise, on 10/10 at like 100/150 AIP will completely kill you, barring crazy nonsense with nukes and electric warheads, right? What would be really the solution to allow players to feel uninhibited while also making it hard enough to challenge Starcraft grandmasters?