Finding a new game that takes your fancy is your best bet.

That said, if you like DotA (and i'm not going to ask why, as i'm sure i couldn't understand it even if you explained ) you might like to try WoW.

Seriously.

You're not going to beat it quickly, and there's no real reason to play a cookie cutter class, so you could just do it fo fun I said fun in the same sentence as WoW - i need to check my sanity :P