I really hate Bran's character at the moment. He's been in exile away from Winterfell for nearly all 7 seasons, he finally gets back home, and can only act like a weirdo around Sansa. Without hardly seeming happy to be back at all. And annoyingly, he of course reaches Winterfell right after Jon has already left, hence not being able to tell him who he really is.
Then you've got storylines like Sam and the Hound which are just kind of floating out there for now.
And somewhere, Gendry is still paddling his rowboat since we last saw him in Season 3. Robert's bastard who arguably has the strongest claim to the throne, given the last 2 kings were incestual offspring and not from Robert.