I play DotA some years already and I believe I know much about it now. I think that it can develop critical thinking but only if players try to analyze the situation, follow their strategy and counter enemies'. However if you don't try to think then there is no much use for your critical thinking.
Some of you are persuaded that it separates us from our friends and parents. It's my viewpoint that it varies for every person individually. I personally didn't have any problems with it. But it's true that you can lose close connection with others if you spend too much time on the game. And if you became interested in DotA I'm sure you WILL spend much time. This is the biggest problem of DotA and all computer games and the main reason of separating with friends. This time could be spent on more useful activities. Also if you want to use DotA for developing your critical thinking you have to know much what means play much because you cannot use critical thinking in new and unknown area.
DotA is really entertaining game and it can develop critical thinking. But there are a lot of other ways of having fun and developing critical thinking more effectively.