I sympathize with 2-4. Those things make it much harder to earn reputation by asking then it used to be. Fixing those problems requires fighting a bunch of institutional inertia, so it will require either time or some sort of judo move.

But I don't understand how having separate sites relates. If you contribute to some of the smaller sites, I think you will find you'll get excellent answers from people more focused on the sort of problems the site covers. Frankly, I've seen DBA questions asked on SO that get short-sighted answers from programmers. Those questions should be asked of people who really know how a database works under the hood.

I can see how collaborative filtering might help. But a big reason people have moved to dedicated sites as opposed to SO is that they want to have separate moderation policies for the questions they enjoy answering. (I've put a little bit of thought into the criteria for spinning off sites on meta.SO: http://meta.stackoverflow.com/questions/271989/does-it-pay-t...)

(Disclosure: I'm a Community Manager hired by Stack Overflow.)