The thing is, the reason for all these fixes and workarounds is partly because the developers at Microsoft are testing their installations on pristine machines with a fresh OS and a brand new Registry. But the developers out here (you and me) aren't doing that. We're installing it on a working development machine (yeah, yeah, I know what they say, but nobody listens) and so we need to uninstall our old BETA or CTP and try to install the new guy. The uninstalls leave orphaned Registry entries (that's the primary culprit) that interfere with the new guy getting in and being completely happy.
So you have junk where you either can't install, or your Help doesn't work, or your IIS ASP.NET Tab isn't there, and so on, ad - infinitum.
So what's the answer? Well, you can't change human nature. We aren't going to stop installing BETAs and CTPs on our regular development boxes. What the people at Microsoft need to do is spend more time doing it the same way we do it, and they'll discover these issues before they make a release.
Hey, nobody EXPECTS a BETA to be perfect. But, you can still do a lot to make the developer's experience a better one.