It's dumbed down, but that's not necessarily a bad thing. I (and other people who want to play games with a high skill ceiling) think it's a bad thing, but some people don't.
Differences are okay.
Last hitting and individual xp is not a high skill ceiling. Stop saying that shit, please.
HOTS have just as high skill ceiling as dota 2 and others.
NOTHING is dumbed down in this game. You just need to learn to play, and understand the game.
I bet you played 5-10 games, and think you understand everything about this game already... :D
Go watch some guides and educate yourself first.