I am just going through our deployment testing for RU6 MP1 now. Thankyou for your post about these problems, every time I look at upgrading our version there is also a post here about that version having issues, problem... I think my bloody presures increases 50% everytime I go to release a new version to our production environment. Because people always remember when things go worng and not when they go right and with this type of product it can go very wrong in a big way very quickly.
On a side note, Cycletech, not relating to this topic but in response to your comments about release notes, I have had a case where the installation of MR4 Mp2 resolved the problem. The release notes for MR4 MP2 did not mention this fix. I was told by the Symantec Tech at the time it was a fix that was not a publicly disclosed.
So you statement is not always true.