Too many dota games. Beside this one has little credibility on being a good Dota game. The few people who will play the new Dota game are mostly the ones that are pretty bad at the actual one. My reason for saying so, if your even decently good at the current dota, you know every skill of ever hero and you know how much each of those skill cost in mana, how much damage they do. You've learn how to counter most of the heros and know whats good & bad againts them.
So most of the good players won't switch to this or LoL because most of them have spent nearly 500+ games learning how the game. So they rather stay in Dota than switch game to learn all over again.
And again, the less LoL has is some of the original creator of the Dota game. This game has no one. DemiGod the first dota attempt was a commercial flop. LoL might have a strong fanbase . But this game, don't see it being that popular. It's going to have its fan's, but that's it. Dota in WC3 will still triumph.