I have read the rules of all three games but never played them. I think Aronsons introduction of square fields to improve the attacking power of the Long Leaper is quite ingenious.
I also thought about some ways to handle the difficulties of attack in Ultima, but didnt try them out seriously. Maybe one experienced game inventor of this site can evaluate my idea better than I do. It goes like this:
Your army is subject to some kind of promotion. This promotion happens, when your king manages to advance to the opposite half of the board.
The power of chameleon, long leaper and pawns stay the same.
Your withdrawer gets the additional power of an advancer, promoting it to a pushme-pullyu.
Your immobiliser gets the additional power of a swapper.
Your coordinator gets the additional power of a triangulator.
Does that make sense?