Hey Jonathan - what console is the competition for? PC, X-Box One, PS4? All?
As for favourite Blizzard game, I'm going to say Overwatch... but saying "Overwatch" is a bit predictable so, I'll discuss my former all time favourite Blizzard game, Diablo II.
I first played Diablo II when I was twelve years old, back in 2000. I used to play the first Diablo before it (when I was eleven years old), which was my first taste of online gaming, back on 'ye ol' 56K dial up.
I was so excited that we were getting Diablo II, I bloody had dreams about what it was gonna be like, then when we finally got our grubby hands all over it, my two brothers and I were so in love with that damn game. Everything about it was so much better than the original Diablo, it was a hell of an upgrade of a game! Five character classes with their own unique skills and abilities, being able to bloody run, huge outdoor maps, EIGHT player multiplayer?! For its time, almost everything about the game was amazing.
While its expansion pack, Lord of Destruction was awesome, its latest patch updates essentially broke the game when they introduced "synergy", e.g. leveling up specific skills, to give bonuses to other skills. It got absolutely ridiculous that my Paladin's Fist of Heavens could cause about 100K damage per strike... and classes such as the Necromancer, Amazon and Sorceress became grossly overpowered, while other classes such as the Barbarian were left behind in the dust.