Cain is still lecturing us from beyond the grave!  Halp!

it was really really short, and it should have ended with D2, seriously.

The story was ok but average overall. I still can't get over Tyrael being human as he was just pure epicness as an angel.
I correctly guessed about the stranger being Tyrael as well as about the wanderer being Leah's father. The kid Emperor being Belial surprised me strangely enough.
Blizzard really needs to make a couple of movies as they have an untapped goldmine while their franchises are still popular.

So the story should have ended with a massive cliffhanger? The destruction of the Worldstone open a pandora box of questions, they had to do something with that. 

Probably D3 story was not the best way to approach it, but if they had ended it on D2 it would be pretty bad.

I was cool with it, everything was destroyed, happily ever after, then comes the renaissance, then the steam revolution, and so on, then they'd be playing an ARPG in a few hundred years or so teaching themselves the history of their world, the end.

Then you're probably one of the very few people that I know that was satisfied with how they left the story after LOD. Not only it was pretty inconclusive, it was really just a "well so you just destroyed the source of Sanctuary, what now?" moment. 

let me clarify without the anger, after D3, I'd rather they just ended at D2, it's too late to remake D3 now.

In that I agree. D3 story's approach was clearly not the way to do it (even though it had some good moments, it was mostly hasty and badly executed). They'll probably try to fix the majority of the plot holes and bad caracterization (Belial and Azmodan were a joke) with expansions, but I don't know how good that'll do.