I am of 2 minds on this, as previously stated, I told Chris Edwards that interchangeable back straps with varying angles and depth would be an easy and cool thing for the pistols. He ran it by Gaston, and I was told, Gaston thinks its perfect, and no.
I have small hands, so performed grip reductions on my m22 15 yrs ago, crude but effective. Soon after Robar started doing the same thing and now there are lots of smiths making money doing it. I started shooting my m21 with a grip reduction, and it became my main auto pistol, now after many years of shooting it, my m17 and m34 without reductions, seem fine.
You take Dave Sevigny who shoots unmodified frames and VERY WELL. That is where the 2 minds come in. If you shoot a Glock only, and learn the Glock grip, learn the glock trigger, it does work, and work well. But if you shoot multiple pistols, the Glock won't point like you want it to and the trigger 3.5 or more will not behave like you are used to. The trigger is still very usable. I have in the past and still do promote the natural HIGH point of aim of the Glock to be a plus, not a minus, as most casual shooters shoot low under stress, due to flinch. They will have a higher point of impact with a Glock than anything else, and that is a good thing. Instead of pointing to the chest and hitting nothing or a belly shot, they may actually hit the chest.
The market is now being heard and Glock is reacting, after a very long time. The Walther 99 and the M&P heard the requests and introduced this feature, Just like the Japanese car manufacturers, listen to the consumer and give them what they want, not what we want to sell. Cupholders in cars, Silly?? Who drinks coffee while their driving.