Wimp my ass...
Unless you're playing on Wait mode or are just a masochist, I cannot see people trying to go without the Gambits. Besides the gambits allow you to build strategies so they are more than just sorry A.I.
As for obnoxious guest characters... My vote is for Reddas. For a renowned pirate who dual weilds swords, he's pretty lousy. He cannot take a hit nor can he really dish it out.