How much of it is Tencent and how much of it is Valve taking too long to finished the beta, implement a tutorial and get a working, low spec dota client out into China? The fact that two Internationals went by before solving this a problem no amount of tongue in cheek "Valve time" can diffuse. LoL wasnt gonna sit around waiting and they knew Riot had an advantage in the Chinese market cause they are owned by a Chinese company. A big company that would certainly do anything to make sure League isnt threatened at all by Dota 2.
Valve dragging their ass is hurting Dota's long term prospects, but at the same time the games could coexist if Riot and Tencent weren't so hellbent on eliminating competition.