Reminds me of https://en.wikipedia.org/wiki/Cell_(microprocessor) and how that was considered a bad direction for game AI and general game depth, at least some were proclaiming it as such, that it would lead to prettier, but dumber games. Didn't make much sense to me at the time and in general I think number cruncher cores were a boon for AI.
Game AI, being simple symbolic AI, has really branchy unpredictable instruction streams. The SPEs were really more optimized for GPU like tasks with clean loops where you can gang together a few SIMD lanes and process them all at the same time.
All of that being said, I've heard from a few PS3 devs that the simple PPEs didn't really do a great job with that kind of AI code either, due to their extremely simple core designs including their branch predictors. So it didn't end up being a concern and a lot of AI ended up running on the SPEs just because they could be laying around with nothing better to process.
At the end of the day, game AI wasn't really held back by a particular console's design.
