If releasing quality updates means delaying release of said update - then delay the release of the update!!!
I used to look up to the Exchange team at Microsoft. They used to be the best coders in the world, hands down. Nowadays they seem to released half-finished code. The latest spat of versioning all the rollups is downright unacceptable. Looks like it is going to be even worse with 2013 because it won't integrate with current 2010/2007 installations, and there are features missing left and right (ex. message tracking missing from GUI, etc).
Get your act together at Microsoft! Exchange is going way downhill nowadays and this is not acceptable. You need to push back any RTM until a proper job can be done testing your products. The onld joke of "you can't deploy a Microsoft product until at least SP1" is really ringing true lately.