More casual? Perhaps, but the game has only been out for two days so I think it may be too early to make that judgement. I see it as a moba with the fat trimmed off and there's a lot about that I like. For starters less fucking bullshit in general, out of the fifteen games I've played I've only seen one negative player and it didn't even matter. Because players have less to be pissed about in heroes of the storm. The matches are shorter, so if you're getting your ass kicked or you have an asshole on your team it's less painful because non like league you wont be sitting there for 30+ minutes just wanting to start over, with a group of two denying any chances of surrender.
With the shorter matches comes easier learning yeah, but league of legends is a game where you fall behind and you're pretty much done. That is to say, heroes of the storm has actual comebacks. I'm not talking about the occasional league come back that happens once in a blue moon, I mean the losing team has a very real chance to come back every game if you squander your lead. In the beta some people called this the game rewarding bad players, but I'm starting to lean the other way now. You can't just do well at the start of the game and then suddenly be too powerful for them to catch up, no more getting fed and blowing up everything that comes within a mile. This is what makes league so slow, your team makes a few mistakes and you're behind for the rest of the goddamn game. Heroes is actually rewarding good play, by expecting you to be more consistent. Yeah you're in the lead, but you're not invincible, you need to capitalize.
Which is great, because heroes of the storm is more team focused than league.
The bad though, obviously there's less content, with the exception of maps.