>>724702964
Roxas is a stronger character due to the circumstances around his existence and how he grew as a person because of it. That's not really enough to carry an entire series, as you said, but one or two games' worth of plots is enough, which is what he got with 358/2 and some of 2.
KH is only allowed to keep going with Sora because he doesn't really have any personal story that isn't attached to the people he meets. He's a very wide as an ocean deep as a puddle character, for better or worse, which is what makes him more ideal as the series lead.
