There has to be a significant pool of questions for a number of reasons, these being the most obvious ones that spring to mind:
1. Brain dumps
2. Informal sharing between colleagues/friends
3. Candidates who re-take the exam
4. Breadth of objectives in the exam blueprint
Personally I thought the VCP5 exam was incredibly fair against the exam blueprint, and the it was the best VCP exam yet at testing whether a candidate had actually performed the administrative activities being test on rather than just having read and memorised documentation, and I hold VCP2/3/4/5.
There are occasions where those who have a significant amount of real-world experience can struggle with the exam, there can be a greater temptation to think "what would I do?" rather than "what would VMware do?"
I would suggest that you email the Certification team if you would like any form of official response to your questions/concerns - certification@vmware.com
Scott.