From what I've seen, Blizzard is doing something new; They're making a game in this genre that isn't trying to be a esport. It's trying to be fun, enjoyable, and good for a few rounds with friends. It's not trying to be the only game you play, like DotA or LoL try to be. They already have a hyper-competitive RTS in Starcraft 2, and they built the engines of Warcraft 3 (which DotA, and by extension DotA 2 and LoL, are built off of). If anyone is the right company for this game, it's Blizzard.
Obviously it's still in "Alpha," so expect much to change, but I'm keeping my eye on this game. If it turns out to be ultra-competitive, it's because the players want it to be, but either way, it had better just be all-around fun. The biggest selling point for me is the lack of items, meaning anyone can jump in and have a good time, without feeling like they have to do research before a play session.