Yes and No in my opinion. If you take them from purely a development perspective, they are really really good. They release their games almost complete, nearly glitch-less. That is one thing a lot of developers fail to do.
If you base it off of a game standpoint, that is really up to each person. Personally I find starcraft overrated, yet I say this because I suck at RTS and hate basically the whole genre. At the same time, Diablo 2 was some of the most fun I have ever had while gaming.
World of Warcraft is a different subject in and of itself. It is the most successful MMO to date, yet at the same time, it ruined the Warcraft lore. Don't get me wrong, I love raiding in WoW, but I am also a person whom cares a lot about lore, so the fact 25 "random" heroes kill Illidan pisses me off.
I am not surprised that this pole is really close. Blizzard does a LOT of things right, but at the same time they do a LOT of things wrong. Truly, a great company.