Speed is a possibility, if it's important to the position.
As to the rest of it... I'm obviously not the one to address those concerns if they're there. But I would think there's some fundamental skills for each position that apply. Otherwise you'd have LBs under center, and wideouts manning the D-line.
Speed is important at almost every position. Also you joke about LBs under center and wideouts on the defensive line but there are people putting up huge sack numbers by putting DBs on the defensive line.
