They've already announced the release date (November, 2005). Considering that's three months from now, releasing a Beta 3 between now and then hardly seems productive.
I understand where you're coming from though. VS Beta 2 is very unstable. I have no idea how stable the CTP releases since Beta 2 have been, since I am not an MSDN subscriber. However, given the attitudes of the team handling bug reports, the only thing
I can hope for at this point is that VS 2005 Service Pack 1 is scheduled for an early 2006 release. They've really gotten bad with the "don't try hard to reproduce a user-submitted bug and close the bug rather than acknowledge the bug and fix it" approach.
Because of this attitude, VS 2005 is not going to be a high-quality release, and what's worse, I don't think the people in charge of it realize it yet, because all they seem to care about are "ZBB's," which are highly inaccurate since most of their bugs are
being classified as "not reproducible" instead of "fixed."