imo the number #1 problem for people who lag the hosel is an over rotation of the left arm in the backswing because they are either A) leaning too far right at top of backswing (for a righty) or B) they swing too far right on the downswing (which can happen from A above).
This leads people into rotating the left arm more to allow them to swing so right w/o hooking the crap out of it.
Do you load the club hard from the top?