I would go wider and say that the best ball strikers have more lag than the worst ball strikers.  I would also say that at some point, too much lag is a detriment to ball striking.  I'm not too concerned with the strength of grip versus weak grip.  I've seen both grips produce great ball striking.  I think the grip style needs to match the swing style.  I'm more concerned with confidence and performance of the grip...like actually holding the club, creating proper club face angles and positions. 

RC