I'd say no Ippon Kumite is a form of free expression after a point that can help in self defense techniques and developing combinations that flow around the limbs of the help mate. Even if defined they force you to make the techniques work.
As for strict trad version I believe the way the kenpo guys do it is best, no step back long stance and attack. Stay at the ready and attack with straight, hooking, uppercuts ands or kick. Here you will find, a punch is just a punch....
Its just a training exercises, just like stagnate hand bag work you defend and counter. 2 man bunkia kumite helps in making you feel your oponents movement you start associating certain movments of the body with certain techniques sorta like learning zoning and possibilities of attack from that movement. It helps you learn to stay in close and make the attacker uncomfortable. As mentioned its just training to build upon.
Really when you start decomposing the kata you are going into bunkia, its already done so why reinvent the wheel, in some schools, in the schools that its not. I'm sure the Instructor has broken it down to moves that can be used for selfdefense. Bassai/Passai even has a stick/Bo defense move in it. So no why reinvent the wheel, its there its already being done. So no new Katas, you might put a back flip in it and start wearing silver and black gis!
I don't do Ippon Kumite much any more, but its good basic training. My 2 cent.