They were focused on Blizzard before Curse bought them. Remember MLG used to promote events on MMO-Champion. The problem is and always has been that WoW was the champion at the time of the sites inception and most of the traffic that comes here is for WoW and Blizzard related products. One of the bigger traffic days for this website was the Diablo 3 launch. However MMO-Champion has covered more then just Blizzard games, when there is enough interest for it. Not to mention there exists a healthy sub forum for non-Blizzard games when the MMO-Champion community is big enough and dedicated enough to warrant a sub forum for a specific game.
You have presented zero reasons for why WoW is not the MMO-Champion. WoW is still with out a hint of bias one of the power houses of the MMO Market. It might have its flaws, other games might do things better, that is all subjective metrics. But if you look at industry influence, subscriber base, revenue over the years, length of time, and market relevance then WoW is certainly the champion of MMO's.
But your entire premise could be denounced up with a few words: You added an 's' to the end of the site name.