I 100% believe that Kanmei possesses more physical strength than Man'U, but I have a hard time seeing Kanmei do any better than Moubu did against Man'U lol.
I think Gouhoumei could have been a great protagonist.
Picture this: his father, the only great general in all of Wei is slain in battle. Gouhoumei is forced to take up the position, and discovers secrets of his father's past, (the Wei Fire Dragons). Gouhoumei will have to deal with the ever growing expansions of Qin, the powerful Zhao generals lead by Riboku, and the Chu forces.
I imagine that if Gouhoumei was the mc, he would eventually avenge his father and defeat Duke Hyou. I guess the main antagonist would be Tou and the Young Qin trio.
Riboku also would have been an excellent main character.
I imagine that a manga centered on him would cover his time in Ganmon against the Xiognu, and maybe his wars with Yan. I think that the Zhao monarchy, Ousen and Sei would be the main villains if Riboku was the MC imo.
I think Houken also would have been significantly different as a characte.r