Why? Because all of those things take away from the fun and pace of the game. Now dont get me wrong dota for wc3 is very fun, but all the denying and gold loss etc makes the game stressful and less fun, at least for me. In dota it is easy to get completely shut down and then roflstomped the whole match. At least in LoL you arent completely gimped the whole game from dying early.
Only thing I might agree with is no loss of gold on death. When a hero gets fed it is a lot harder to cut them down, since even if you kill them it doesn't really set them back. They lose EXP/gold while they're dead, but that's it. --- No amount of planning will ever replace dumb luck.
Oh, and another one which ties into the whole "no gold loss" thing. Since there is no gold loss, even if you play extremely well as a caster at the beginning, it means **** all because late-gamers will inevitably be farmed as hell, this basically implies that caster heroes are substantially worse. Along with that, it also cheapens the value of hero kills. Even if you're up 20-0 kills, it means nothing because like I said before, no gold loss.