Is it truly a good thing to move from a STOC/FOCS/specialized conferences system towards a STOC/FOCS/SODA/other specialized conferences system?
I'm surprised there is even a debate over this. Specializing conferences creates more interest, and you know what to expect. If we think of a conference as a group of people with shared interests, what's not to like.
The problem is the traditional role STOC/FOCS have played in "defining theory". I have actually heard arguments that since CG papers are not sent to STOC/FOCS, CG is not theory. It's about time (and in fact this has happened for many years now) that people realize that STOC/FOCS are slowly becoming specialized conferences. Bill Gasarch asks what their specialization is: a lot of it depends on the current hot topics of the day. It seems to me that as an area of theory gets hot, it starts getting more papers into STOC/FOCS, and as the hubbub dies down, the topics move on. SODA on the other hand, has a fairly stable set of topics that are covered, with variations from year to year in terms of which areas are represented more.
Update: Our strait-laced theory community is letting it all hang out. Join in the fun :)