As I understand it Seguin does that stuff too and is a little more "complete" than Hall, thus why he plays center. I want the guy who can do the most different useful things for the team when called upon, especially if he does them all at a solid to elite level, and for me that sounds more like Seguin than Hall.
Besides, from all I hear, Seguin's doing it with a worse supporting cast and that sounds more like the Bruins' situation. Maybe I'm overthinking this but if two guys are both real close in talent, IMHO you take the one from the rarer position -- draft for talent rather than need IOW. After all, having too many talented centerman is a great problem to have anyways.