Good question and observation. If we go back in time to before the MPF was created and look at all the irons (most of the irons) that were available from 1988 to 2003, 34% were in the GI, SGI or UGI cateogries and 66% were in the Conventional, Classic or Players Classic categories. After Ralph’s book came out, we started to see a shift and in the next 3 years (2004-2007), 68.5% were in the higher playability categories and 31.5% were in the lower. Just coincidence? i don’t beleive so and it was a good thing for golfers to have access to more playable clubs. Over the next 3 years (2008-2011) there was some backsliding with numbers dropping to 53.5% and 46.5% respectively. Some good and not so good years since and as of today, taking into consideration all irons measured from 2004 to 2020, the percentages are 59.3% GI, SGI or UGI and 40.7% Conventional, Classic or Players Classic.
I do think there was a time when designers were more willing to go more extreme, lead by Ralph, in certain dimensions that create the really high numbers. The two key features to get the 1000+ numbers are blade length and actual vertical cg. Blade lengths need to be long and cg’s very low to get to the really high numbers. On the extreme side we had Outburst as you mentioned and then the Glider, the Recoil and several others that were definitely different looking and but great performers, but sales were only OK. Our original KE4 was the least odd looking iron that exceeded 1000 points and was our flagship model for years. We still carry a version, but in an effort to appeal to a few more that needed Ultra Game, but were not willing to play the extreme looking iron, we modified it and the current KE4 S is 863, still in the Ultra Game Improvement Category. The new M890 (980 points) almost cracked the 1000 barrier, which was our goal, and I think it is not so extreme in it’s look that for players that can truly benefit, it will help their game. I believe the products we have developed over the most recent years do a good job of offering high playability in multiple categories, while still having product that appeals visually to a broad range of players.
As far as other companies, I do think there is a fear of having something too extreme in look. More specifically they are not willing to extend the blade length. Based on my observation (and I measure every iron for MPF ever year) I believe the cosmetic is of greater importance than the playability in many cases. Not in all cases and some manufacturers do a great job developing highly playable clubs. What drags the number of playable models down is, in my observation, are the multiple “Players” models you see companies come out with that are designed for tour players and then marketed to the masses. Short blade lengths, narrower sole widths, higher cg’s, which are features that don’t really benefit ANY players. You have to be tour quality and hit every shot solid to get any performance out of these types of irons. The mass and dimensional characteristics on these types of models do nothing to enhance performance. Still, they often times look cool, traditional and that is something some players want to play even though they shouldn’t be. The silly thing is that you can have classic looking iron designs and still have great playability by simply paying attention to the dimensions and mass distribution in the design. We have seen a few get there, other than our own designs, but not many.
As far as moving to the #6 iron fro the #5, we did that because as time went on the #6 became more of a middle iron than the #5, which was considered the middle when Ralph started collecting the data. In Ralph’s original book, he measured the MPF for 9 entire sets and in looking at those models from 2004 and earlier, the point spread between a #5 iron and a #6 iron within the same set ranged from 0 points difference to 71 points difference. The average was 31.7 points.
With regards to workability, if we assume on center hits, the fact is all clubs are workable to the same degree. If you miss hit slightly while trying to hit that cut or draw, the less playable the club the more the ball will move. The higher playable clubs are simply more stable on off center hits and this causes the ball to move less. Again, this is on OFF center hits. Club head path, face angle and club head speed have always been the determining factors in how much a ball moves. I will add that clubs with lower center of gravity can be more challenging when trying to hit lower shots, but sideways movement when discussing workability is always about the path, face angle and speed.
Hope this helps and with regards to your #7 wood and #9 wood, your ahead of the curve. I wish more would play the highest playability clubs possible throughout the entire bag so they could see just what a difference they can make.