Not really, lots of great studios existed before and now (Black Isle Studios, very early Bioware, Piranha Bytes, Origin, Looking Glass Studios, Ion Storm, etc). But Blizzard always made really shallow games with a ton of polish:
- Diablo - People praise this game like it's the second coming, but the reality is, Diablo was inspired by the much, much, much deeper NetHack, and was originally supposed to be a turn-based game, before it eventually turned into a click-fest. If you want to see what a deep, intelligent version of Diablo looks like, buy Vulture on Steam for $3, and spend the next 20 years playing it without looking up online hints.
- Starcraft/Warcraft - very simplistic RTS's, where all the complexity comes from human competition, but I mean you can play basketball outside too, this is not what great games are about.
- World of Warcraft - was fun in the early days, but really, they took everything interesting and multiplayer about MMOs and over time turned it into a single-player lobby full of mini-games.