Now I am curious, the thing I like about Vollo/Mordenkanien etc. is that they can be unreliable, prejudiced and what ever and that gives the DM the opportunity to subvert the common beliefs.I think you're misunderstanding me, or I am misunderstanding you.
I don't like orcs always having to be evil and stupid, as that depends on setting. Thus, I didn't like the original Volo's Orc Race, and prefer the Eberron/Exandria one. I like that they errata'd the book to get rid of that original race. It is easier for me to just ignore the orc monster stat blocks in the MM than it is for me to homebrew an Orc race (before Eberron/Exandria Orcs came out, that is).
The MM descriptions in the past were represented as accurate and things like racial alignments were the result of fixed cosmic ordinances, where as Vollo's Guide is just reportage by some bloke.