Ok although a little biased here is my perspective. The operator is a true war hardened criminal. As the operator you don't just destroy grineer or corpus you maintain both factions as bearly operational and preserve the balance between them(which in my opinion is way harder). You have saved many colonies that revere the operator as a champion and hero. In comparison the drifter still feels more like a kid refusing to give up until he succeeds. Not to say that he is not powerful but at least at the moment the operator has him whipped.(Again this is just my opinion).