you underestimate the quality of the games blizzard makes!
there are very high chances that it will smoke both LOL and Dota 2 on release! Coz the experience provided by blizzard is just different all together!
For example Hearthstone, its an instant super hit, its a copy of MTG but really well executed!
You can counter say that diablo3 failed hard coz of no endgame, but diablo3 core game mechanics, the programming, internal design, is the best out there!
you should understand that dota was built on top of the warcraft engine made by blizzard, which was further developed, copied to make LOL and Dota 2
And no heroes don't resemble dota 2 chars, all heroes are from blizzard past games, they use their spells from previous games!
Y'all know that this is the game fuelled by Butthurt after Blizz lost DotA to His Holiness Lord GabeN of Valve