bloodroses75: Blizzard has never really been innovators or imitators. More of masters of refactoring.
When Warcraft and Starcraft came out during Age of Empires, Empire Earth, Earth 2140, Total Annihilation, Command & Conquerer, etc... They found what they felt made those games and stripped out the rest.
Diablo was against Gauntlet Legends, Dungeons & Dragons, Dragon Slayer, and so fourth. Again, found what they thought was fun and stripped out the rest.
World of Warcraft was not the first MMO and nothing exceptionally innovative compared to the competition and many felt it would be a short lived reign before Everquest 2 came out.
Brawlers may have spawned from their custom map editors but they did not create or innovate that genre. DOTA, LOL, HON, Smite... This market is already saturated as well. They are just putting what they feel is fun about it and stripping out the rest.
Blizzard is doing what they always do; trying to take what they like about a genre and make their version of it that they feel is fun, and if they do not feel like it will stand up to their standards then they will scrap it. It will not be fun to everyone but will be a Blizzard game.