It's not even like they could have done nothing with Bran Stark. I saw a lot of fan theories about how all the weird shit going on in later seasons is because the whole thing is just Bran's dream, and he's getting sicker/more feverish, that sort of thing. And it would have been a good twist, especially with the Hodor shit. Like toward the end he has an apotheosis because he can lucid dream, and it ends with him having some kind of religious experience right before waking up, that ends up being the Song of Ice And Fire, and is in turn basically scripture or some shit f or future generations.
That sort of writing would have been actually cool. Some of the scenes where Bran touches the tree and has the trippy visions played into that as well. They COULD have written Bran Stark as a visionary prophet or something, but they just didn't. The ending was retarded.