Bran's gotta be the greatest unused resource in the whole show. I mean, I'm sure it gets tiring sometimes with the seeing the past thing, and the warging and all of that, but instead of parking him by the tree all day, maybe try asking him every possible question you can think of about everything you ever wanted to know about? Varys would know what to do with Bran, as would pretty much everyone in the khaleesi's inner circle. The starks, not so much, at least yet.