Personally, I like Ashe. People liked her husband, who led the kingdom into a successful merger. Still, we can’t really judge Ashe based on her husband’s deeds; that’s a bit unfair. Taken on her own merit, Ashe seems to be a bit manipulative, cold and ruthless. She’ll do anything to accumulate power and avenge her kingdom. May not be so great for foreign policy, though has had many adventures in foreign lands…
I believe Vayne wants to make Dalmasca great again. He wants to put the reins of history back in the hands of Man. Vayne seems to speak at the people’s level and he’s somewhat of a celebrity. But his insistence on banning the Occurians from coming into the kingdom is a bit too much. Plus, his ability to turn into a demon when challenged is scary.

If Vayne becomes emperor, many will move to the Mosphoran Highwaste (i.e. the Great White North).