@misnomer You may be right about the writing. But: I never lilked Marcus either, his facial expressions are always so overacted and hes an obnoxious bitch, but hey, maybe thats how he was written.
I don't think Jason sucks, he just isn't interesting enought to be a main character. Imagine Season 3 with Jason as a side character, fighting with Stylax about who gets more ladies. Would have been amazing.