1) Well, since the King wants to marry her, she must find a suitable husband. In this case why not make a third game in which you need to deal with a few contenders for the hand of the princess?
2) A few new classes will be nice and will add replayability. Classes can be reworked to suit each race (many different contestants for the princess' hand) - humans, elves, dwarves, orcs, undead, dragons, demons - everything goes. Wanna be the vampire husband of amelie? Wanna give your dragon heart to her (we saw that in KBTL)? Wanna be the demon incubus who will possess her till the end of her days?
A lot of things can do well here, and all of the contenders will be unique - Human Champion, Noble Elven Ranger, Demon Incubus (like Agvares, he is an incubus), Undead Vampire, Orcish Chieftain, Rich Dwarven Foreman, Young Dragon, ready to commit to someone.
Although I would feel sorry for poor amelie if she gets a stinky hairy drunkard dwarf for husband... At least the kingdom treasury will be full all of the time
