Do they have things like divorces in Westeros? Could Rhaegar have ended his marriage to Elia and married Lyanna in secret? I'm assuming not, since people seem to just father bastard children instead of breaking up, but maybe he was a revolutionary in that way? Obviously, due to its backwards gender politics, it would have to be the men who enacted the divorce too, which is a problem.
As to the acting, I think to a large degree, it's a matter of the characters. Up until now, Dany and Jon Snow have been played as the traditional heroes of the story, thus they don't get the best lines or ever changing character arcs like others do (Jamie, Tyrion, Sansa, The Hound). In fact, while almost every other character has some shade of grey, both of them are straight-forward: Dany was the victim who became a queen and Jon is the bastard who became king. I think both actors are fine in their roles but they aren't asked to do much, aside from proclaim and brood. Maybe the final few episodes will unleash more nuance for them. Also, let's be honest, heroes tend to be boring, it's the villains and rogues that are fun to play and watch.
I really would be interested to see if the final season or two for the show ends up being like the Return Of The King's Oscar victories, where the final chapter saw it be rewarded for everything. Dinklage is rightly praised as being wonderful, but I have to believe others will get some rewards for a job well done.
Take care all.

