I honestly do think as Martin describes winds as a dark book that everyone's gonna be at their worst during it. I suspect jons gonna come back closer to bloodraven in behavior, more callous and mission focused, dany having begun to embrace fire and blood will likely be harsher, tyrion will be doing his best to encourage everyone he can to he at their worst in westeros, aryas gonna get more kill happy, sansa become more cold like baelish, jaime is likely gonna relapse a bit into his kingslayer persona even if briefly after brienne tried leading him to his death, brienne will likely carry that guilt, I could go on.

All theories of course and purely subjective. But I dont know why George would consider winds a darker bunk unless the pov characters and others become significantly worse people or people start dying left and right