"Cheap job," said the intellectual.  "Well below the rate.  Should be half the kingdom and his daughter's hand in marriage."

--Terry Pratchett, Guards! Guards!

Something I would like to see would be the ability to marry off my children to my recruited champions.  I don't see any reason why it shouldn't be possible--after all, your sovereign's spouse is going to be a recruited champion, and it would add in the ability to "reward" particularly loyal/powerful champions by making them your in-laws.  If you're worrying about royal blood being diluted, it's already been cut down with your sov's first spouse, who's going to be a "commoner," so why not give your favorite heroes the chance to spawn babies, too?  I don't see it unbalancing anything: you don't have to deal with other factions to get more babies, true, but you don't get the bonuses for doing so, either.  It would also prevent, or at least help stave off, the massive incest that seems to be the inevitable eventual result of doing things the standard way...