You are far more knowledgeable than me and a lot better at expressing possible problems with an intelligence explosion.

I don't know about that. The primary issue I've talked about limiting an intelligence explosion is computational complexity issues. That's a necessarily technical area. Moreover, almost all the major boundaries are conjectural. If P=NP in a practical way, than an intelligence explosion may be quite easy. There's also a major danger that in thinking/arguing that this is relevant, I may be engaging in motivated cognition in that there's an obvious bias to thinking that things close to one's own field are somehow relevant.