The thing is, all of that stuff would be allowed under the restriction you were objecting to.
I don't care that much about what's allowed but about what people actually do. Even if a nerd intellectually understands that mind-body dualism is wrong, then he can still ignore his body and avoid exercising because he doesn't get the idea at a deep level.
Why do you consider something that changes hormone levels keeping biology constant but something that changes genes not keeping biology constant?
More importantly, once you understand that there a lot of unexplored space the question of how far we could improve becomes a question that obviously nobody is going to be able to answer.
Couldn't you have said the interesting parts of that without the aggressive 'You're being a mind-body dualist!' part?
I suggested recently that part of the problem with with LW was a lock of discussion posts which was caused by people not thinking of much to post about.
When I ask myself "what might be a good topic for a post?", my mind goes blank, but surely not everything that's worth saying that's related to rationality has been said.
So, is there something at the back of your mind which might be interesting? A topic which got some discussion in an open thread that could be worth pursuing?
If you've found anything which helps you generate useable ideas, please comment about it-- or possibly write a post on the subject.