I feel that a large amount of the ire directed at this film is due to last two previous entries' disappointments.
Regardless of that, I think its intriguing how much this film seems to be trying to actually explore the time travel elements more than all the others. It reminds me somewhat of the way Back to the Future 2 played with the structure of the first BTTF, which was rather enjoyable.
I agree that the screenplay creator's link to the modern Dracula movies is troubling- so I am hoping that this movie's screenplay is much more from the creator of Shutter Island (which I loved).
On another note, I was fairly bummed when the 'Sarah Connor Chronicles' was canceled. That show had a lot of cool ideas and was the best thing in the franchise in years.