Due to my recent foray into style over substance, I have a StJ/WP brute named Bantam Betty at 42. Being a boxer (granted, a dirty one since heavy blow is sometimes an elbow to the face) she doesn't have access to the powers using feet. Soooo, yea, no rib cracker, shin breaker or spinning strike. Skipping the three best powers in the set, yay!
But what it left me with was an easy setup to utilize the combo system.
IS-Boxing-HB-IS- (3 levels are up) then either sweeping cross or crushing uppercut. If I miss with either IS or HB, no combo buff on SC or CU but it just doesn't matter as my chain doesn't change.
I also have a StJ/Inv brute that will follow my normal max recharge/tight AF attack chain using the best attacks method but I've yet to sit down to see where she'll end up but it's very doubtful that I'll make any attempt to leverage the system there. It'll either happen on its own or it won't.
And that's the kind of combo system that makes sense. It shouldn't shoehorn you into any specific chain, ever. They absolutely should NOT be forcing players into sub-optimal chains that might also happen to look/flow like shit.