The only hint was the thing where Blackwood's son was musing on the dates being out of whack, which could be interpreted as a genuine concern that Westeros' history has been hugely corrupted or a hint that the maesters don't believe it's possible for those kind of dates to be realistic, so are retconning the histories for their own purposes (the same way they seem to be opposing anything 'truly' magical).

But for the most part I think the maesters' story is going to be held back for TWoW. And it's going to be tough to do the Sam-learning-to-be-a-maester story convincingly at the same time he has 55 other storylines of reasonable importance going on simultaneously. In fact, I don't think it's possible. What I think will happen is that Sam will do some very focused research on the Others, discover a big secret relating to them, their motives and weaknesses and so on, and will get his tail moving back to the Wall pretty quickly without trying to become Kvothe Potter. In fact, if Aeron can bring down Euron and Asha and Theon then bring the ironborn onto Stannis' side, maybe Samwell can catch an ironborn ship back up the west coast to the Wall? It'd be much faster than sailing all the way back around the continent again.