That's true,
I have handled a 4th gen G22, and it did have three interchangeable backstraps. The smallest was very slightly smaller than the current grip offered by the 3rd gen. I really didn't notice a difference. The other two backstraps were larger. I definitely would have prefered an option a little bit smaller, but that's about it. The grip changed a little as well, but didn't seem to change the feel in my opinion.
Boarder