montuckyhuck has it right. Demo, demo, and demo again. Try the SuperStar (again), the Molan, Project, Kingpin, and Biscuit. Keep a boat for river running, and have a playboat for just playboating. If you take the playboat downriver just have fun with it and expect to be upside a lot more.
Any modern playboat that you buy is gonna be a mediocre river runner, at best. Who cares! My All Star is a horrible river runner, but it is one of THE best playboats I have ever paddled! I paddled a Large Rev before that and a Project 52 before that (I still LOVE the Project, but WS needs to get their crap together and start producing a plastic version of the 56 gallon fiberglass Project). If you think the Super Star isn't maneuverable enough in features it's possible that you might be too small for this size, or it simply could just be a user error problem.