The issue is actually 100% not with vBulletin 4.2.2. All 4.2.2 does is expose bad programming practices that PHP will let you get away with if you suppress the warnings.
All versions of vBulletin prior to 4.2.2 had a badly coded error handler that discarded programming standard warnings. These warnings are issues that could become way more serious in the future if newer versions of PHP decide to enforce these standards.
The reason why people complain is because people with no knowledge of programming do not understand this, just as I do not understand a single thing about how an engine works.
All the users see is "4.2.1 didn't crash my forum, 4.2.2 crashed my forum. Therefore 4.2.2 is broken."
Hopefully I have adequately demonstrated why this is 100% fal;se