I don't really see Dean as unequal. He's just not annointed/chosen/predestined. He's stepped up to the obligation/job/whatever. Anyone COULD do it, but it takes a special person TO do it.

And the fact that he's not obsessed, but he knows it needs to be done and goes out and does it every day. That's character, right there. It's the Xander factor, almost. No special powers, but you stand up to kill the bad things once you know they exist, even though you don't have the special abilities of those around you.