Knock on the pistol?! How many polymer frame pistols are you aware of that offer interchangeable grips?
If changing grips is a major want or need, a metal frame pistol is the proper choice.
Quite a few have some kind of adjustable grip these days. Most are just blackstraps, but my HK has different palm swells as well.
If you are willing to have the grip frame altered, I'm sure the guys who machine and add grip screw bushings to the Ruger MKII 22/45's that came without removable grip panels, would love a new market to open up as those guns have to dry up at some point.
Grips and backstraps are two completely different things so your assertion that "quite a few have some kind of adjustable grip these days" is not only incorrect, it's misleading. Interchangeable backstraps are obviously not what we're talking about here. Why? Because the Phantom itself has them!
Yes, my Heckler & Koch P30L has interchangeable grip panels. They are hardly the same thing as an actual interchangeable grip as found on metal frame pistols, but, for argument's sake, let's concede that they are. Your "quite a few" is, in fact, an H&K model that is very possibly the only pistol in existence with this feature.
My initial statement still stands. If interchangeable grips are important to the buyer, they would be better served in buying a metal frame pistol that offers them the ability to change grips at the cost of a few minutes of their time and a screwdriver. This option involves infinitely less work, less time, and less expense than buying a new polymer frame pistol and having the grip frame altered which you suggest as if it were a sensible alternative. It's really not. The Ruger 22/45 you brought up is a perfect example. When Ruger saw the market desire for interchangeable grips on their 22/45, what was their solution? They dumped the polymer frame and replaced it with an aluminum one.
