Nice intro.
I play Dota since first version on Warcraft3. Now I am playing it for fun, in free time. I must say if you give too much time for Dota2, You will get addicted very soon :) But on the other hand, its really a mind game, because you need to be prepaired for everything. There is a lot of thinking in second involved. So yes, I think with games, you can develop a good thinking skills.
I play Nuker/Disabler/Support/Carry. It depends :)