The proposals here are often very specialized and mostly hobbies of programmers succeed due to the limit that a beta needs a minimum amount of 200+ users.
Especially on scientific topics where you try to attract students with no strong computer programming background it's much too tricky what Area 51 is at all if you visit Stack Exchange for the first time, they will just visit Digg or similar to ask a question. Likely this changes with the ongoing future. So be much more patient!?
It's kind of tragic, that neither biology, psychology, chemistry is yet in a beta here, the quality of these sites will anyway be mainly determined by students and experts in this field, not 200+ rep users browsing around topics/sites related to programming. But probably the Area 51 system is technically not so flexible to make an exception here. I understand you want to guarantee high Q&A quality from the beginning and set up some trustful high rep users and moderators this way, but do topics like biology and chemistry really need such a long commitment phase?
When I look at philosophy or astronomy the amount of regular experts is below a dozen, experts are already now complaining about the quality of questions, so this is a bit too delay and effort to yield this result. For smaller ambivalently specific proposals like Christianity or Skeptics this Area 51 process steps is highly useful and necessary, otherwise a mess to moderate, but for the above topics the commitment constraints look pretty pointless to me and avoid stronger community dynamics on short time scales. So you follow once as a non-programmer and then never come back...
You have higher quality on physics.SE and some expters because of unique selling propositions like MathJax Latex editor, tagging, search, etc... And many physicists programming for a living or in research. It's not like the commitment phase set up a super high quality here. That's mixing up cause and effect.