I agree.
I think the time travel silliness is in part so they could shoehorn the Tower of Joy sequence in.
I find the idea of Bran somehow being the NK frankly absurd, as ridiculous as the notion that longclaw is 'alive'.
Yeah I don't think there will be any time travel stuff. Like you said, tower of joy shoehorned in. Hugely important scene that they overlooked back in season 1 and had to get it in. Bran seeing it was the perfect answer although raised more questions for non-book readers.
In any case the time-line seems completely linear, even if it transpires it's Bran who,
Drove the Mad King Mad with whispers (although I think it more likely it was his predecessor who did that.
Anyone disappointed with the overall main story line? its been done many times before (Mass Effect, Babylon 5 to name a couple)
Not really, it was started a while back and while the theme of a hidden enemy lurking in the background has been done lots of times it more about the stories and events that take place within the overall story. The journey if you will
Besides, there might be a couple twists yet to come.