Haha oh yeah first 5 levels intro, that was pretty interesting. Though I must say it does become a bit of a Diablo 3 feel in story after we meet "Leah"...
Overall it's a typical Diablo story - some mystery, some prophecy and unclear plot - once again you don't have an obvious big bad. Like Lilith is presented as one, but over the course of the Act 1 you do start to wonder.
Also true, starts good, but then sort of trails off fast.My only worry is Blizzard blew their load on story at the start, because the story at the start of the game up to Lilth in the church was awesome and there wasnt anything on that level post that. Maybe blizzard are not done yet, maybe there is better to come and we haven't seen it, but the earlier half of act one just trumps the later half.
I do have good feeling about how it will continue, so there might be some interesting stuff just yet. But yeah, Act 1 is like 10 mins of awesome and then a few hours of "ehh" as far as story goes.