The data is skewed because of the injury in Martinez' fourth conference game. There's a clear drop-off after the injury vs. Missouri. Against K-State he was fine, against Texas he was OK, against Oklahoma State he was fine, against Missouri he was OK, then injured. You can't simply look at the year and say, "Yep, he struggled in conference" because you don't know whether the injury made him struggle or the better competition, or a combination of the two.
Personally, the jury is still out for me. Martinez did some things that made me perk up like no quarterback has since Crouch. He did some things that were the worst things I've seen since... not sure when. He was both very good and very bad. His behavior was open to question as well. I'll welcome him back next year with open arms, confident he'll have matured and improved, but if we have someone better, I'm all for that guy, too.