| well, pizzaz is entirely up to the conscience of the individual. Yeah, that's a simple part technically, harmonically, whatever. It's also perfect exactly as it is. If by "sax solo" you mean that riff between sections, the bass is silent there.
My two cents, the thing to take from James Brown parts is the time and articulation. Those are really big things, nothing to sneeze your nose at. Get it off the record the way it is, move on to the next tune. Those parts don't really need improvement.
That's not to say you can't improvise on them. Cold Sweat's a great one to jam on, infinite possibilities within the framework of that basic riff, Sex Machine is another. I Got You, maybe not so much. But basically you want to get the part, on the record, down cold first. There's nothing you "should" do there, other than just nail the feel. | 
