I think "whether it will be any good" is a valid question, but it's one that can't simply be answered by the length of the Hobbit book.* Once we move beyond that point can there actually be a meaningful discussion rather than a superficial one.
The question I've brought up before is the split. The two movie split:
made a lot of sense.
But I'm unsure where to split it in three. That's the biggest concern I have.
* I believe this is where you would add a "One does not simply judge the quality of a Hobbit movie by the length of the book" joke.