I get this question often and the first thing I say is playability is playability. The mass and dimensional characteristics of the head absolutely tell us how stable and how forgiving the clubhead will be. When you look at irons that have MPF’s that are lower, what we usually say is that better players are the only players that will see any performance out of these designs because they are more consistent in their ball striking. Does not mean that they should play those type of designs. I have worked with a lot of players, tour players included, and they all mis-hit shots. More than you realize. So, in my opinion, if results are the players primary goal, all types of players should play the most stable and forgiving head possible. That being said, I understand that cosmetics and the”look” can be important. For instance, I like the traditional blade profile. So, I play the high MPF playability blade design, our DBM Forged irons. With regards to the vertical cg location, you are correct in the assumption that a tour player might not need a design with an extremely low cg. He may have to work a little harder to keep the ball down with an extremely low cg. However, as lofts have decreased, cg’s have also had to be adjusted a little to make the stronger lofts more playable. A strong loft and a high cg are not good for anyone. It is important to understand that even for the best players in the world, the vertical cg has to be driven below the cg of the ball for the “hit” to feel solid. Also realize that the vertical cg is just one aspect of the MPF. Horizontal cg is critical in how stable the clubhead will be and the rearward location affects stability as well. Both impact MOI. The fun thing about the MPF is that if you know what the top ball strikers are playing you can look at the MPF and see what the number is. If it’s a model we have not measured, chances are we wil be. Finally, you are right on the “working the ball” comment. Ralph did expose it. Enough said.
Hope this helps.