Just the opposite, I purchased Diablo 2, Warcraft 3 and Starcraft plus all expansions and never once felt I didn't get my moneys worth. In fact they still update and fully support games that are 15 years old, I love them for that.
PVP is not the main focus of D3 but will be a welcome addition, WOW did not release with battlegrounds but you did world pvp instead. I played on sargeras and Southshore vs. Tauren Mill was the best pvp area ever :P.
I think they are making these decisions to get the game out relatively "soon". The co-op will be so much fun I'll wait for the polished PvP system.