BMI is not calculated at this moment, he will be active in next versions of engine. I think that now all players have BMI 25.
there was/is a special additional little programm that you can install to your browser. it counts the skills for your guads (gs) and for your c (cs) toghether. So you can see at one view, how good your player is on a certain position.
Yes you are right, that is one type of centers. For exaple you can create PF with SHO (Shoot) and some SPE (Speed) with tactic order to paly outside, and you created Nowitzki type of big man, who can shoot for three ;)
Players without speed will have problem to defend this type of player. So if you scouted that opponent have heavy centers you can attack them with this kind of light center and make some serius damage ;)