I came from a long history of Dota :P.
Problem with Defender of the Ancients, vs League of Legends is how they are balanced.
In DotA you don't hear people bitching and moaning about balance because every defender is so god damn broken, whacky, cheesy, and powerful that there is no concept of overpowered. You just have the one champion that everyone unanimously hate except for the 12 year olds who main em, Rikimaru. Not just for the perma-stealth because so many other defenders have that ability. But because he's like the very first f*cking champion a new player will see with permastealth. They use him, see how easy he is to play when they go on a rampage, and only play him. So the game is then balanced around items.
Compare this with League... that tried so damned hard to balance items and champions... and you get problems when you add the Black King Bar. Or hell the f*cking shroud or knife that gives you invisibility.