Yeah Jon’s parentage explained (obliquely) thus making him the only viable hookup for Daenerys.
I think Jaime will be the one to kill Cersei. He did not look happy at the end of the last season.
Also, they already know the secret of dragon glass (that it can kill white walkers) but it can’t be made; it’s naturally occurring (although I suppose he might figure out how to get a load more of it). I reckon Sam will be the one to save the day at the end (possibly making up for his earlier cowardice via some form of heroic sacrifice)
Hopefully Bran will do something interesting as he’s had one of the most tedious storylines so far! (albeit with some cool bits that have furthered the plot/explained stuff)