I didn't find Rossiu to be that bad. I mean he certainly did piss me a lot, but after episode 20 when Simon beat some sense into him I kind of understood why he did the things he did.
He may not have been making the best decisions but he was doing the most he could considdering the position he was in. And he's sure a heck of a lot better than other characters who are just annoying for no reason at all.
I actually don't remember that. I mean, I remember Genome saying that he hadn't fought anyone very strong in a long time but I don't remember him mentioning another man. Which is surprising since I've seen the series 3 times now...
Though if what your saying is right, I honestly don't think it could be Kamina's dad. After all, his corpse was found a extremely long way away from Tepplin city. And I'm pretty sure we all know Genome isn't exactly the type that actually goes out into the field and fights. He'd rather his enemies come to him.