All good points.
I'd focus on #4 as the primary point. Focusing on theoretical safety measures far ahead of the development of the technology to be made safe is very difficult and has no real precedent in previous engineering efforts. In addition, MIRI's specific program isn't heading in a clear direction and hasn't gotten a lot of traction in the mainstream AI research community yet.
Edit: Also, hacks and heuristics are so vital to human cognition in every domain, that it seems clear that general computation models like AIXI don't show the roadmap to AI, despite their theoretical niceness.
For a great-if-imprecise response to #4, you can just read aloud the single page story at the beginning of Bostrom's book 'Superintelligence'. For a more precise response, you can make explicit the analogy.
I'm giving a talk to the Boulder Future Salon in Boulder, Colorado in a few weeks on the Intelligence Explosion hypothesis. I've given it once before in Korea but I think the crowd I'm addressing will be more savvy than the last one (many of them have met Eliezer personally). It could end up being important, so I was wondering if anyone considers themselves especially capable of playing Devil's Advocate so I could shape up a bit before my talk? I'd like there to be no real surprises.
I'd be up for just messaging back and forth or skyping, whatever is convenient.