MLB is always the leader, but the FS is who has to analyze the offense and communicate the package and assignments right?

No the MLB handles all the assignments and packages; he is the only one on the defense who can listen to the coordinator from the field with the ear piece in the helmet

I guess it could vary from one team to another, but you regularly see the MLB in a 4-3 being the defensive player with the mic calling out the defensive play in a given situation, and he also is the one in charge of calling audibles and line shifts, so I would have to put him as the defensive "QB" before any other defensive player - in this given situation at least.

Hmmm, I guess the FS only has to tell the MLB what the offensive package is then, but I know they have him 15+ yards back for that reason.

hes a darn good football player, hes been put in spots where he did'nt handle things to well but it can be corrected, way to many times he has taken the wrong angles on playing the ball, missing a great breakup or even a pick or 2. its all coachable and can be corrected. maybe there was to much on his plate in his 2nd year?

One of the reasons they wanted to move him to safety was the lack of speed. They were afraid he'd get beat by the quicker wide-outs. In the nickel, it wouldn't be an issue though.