The marriage game is a slow-paced proposition, indeed. You might want to try the non-Westerosi rulers for more CBs in the GOT mod, since the ones on the island do not have any real CBs against neighbors. Also, I generally manage to snag 2-3 kingdoms through marriage in the first bookmark as Torrhen - marry the heiress of the Stormlands, get rid of your heir so the kid from the marriage inherits both, then go for the Rock or the Reachlands by betrothing your heir to a daughter and assassinating all other potential heirs.
And in general, CKII is a slow-paced game, unless you, as you mentioned, have de jure claims or religion/culture-based CBs. Hopefully the next DLC will give us some more things to do in peacetime.
And in general, CKII is a slow-paced game, unless you, as you mentioned, have de jure claims or religion/culture-based CBs. Hopefully the next DLC will give us some more things to do in peacetime.