I played a little bit recently. I'm having a lot of fun with my WD trying out new things and seeing what is viable now. She is only Act 2 Nightmare because I got distracted with other things, but I find myself enjoying the game when I get enough time to poke my head in.
As for the story be 'embarrassingly bad', I really don't see anything different between it and your average action movie.
1) Meet the hero (Leah and your character)
2) Exposition about circumstance that will need resolving (Saving Deckard)
3) Call to action (Deckard Cain's Death and Tyreal's Abduction)
4) Big Boss Fight (Butcher)
5) Resolution (Tyreal remembers who he is and why he came.)
Throw is some more 2-5 with an additional 6) A person believed to be an ally betrays you, and you have what would be a long Action Movie. Do I wish I got to visit more of Sanctuary, yes I do. Do I wish there was some more characterization of the main characters, certainly, I eat that kind of stuff for breakfast. Is the story bad though, I contend that is is not. The story is an adequate Call-to-Arms tale that does very little to deviate from the norm, and didn't try to act like it was anything else.
That said, all of the conversations with the followers and the side-quests were stellar, in my own opinion of course.