With my new 19.5 with Ameriglo sights, there is nothing that I think needs changing (except for getting a gadget when they become available). I also have a new G43 (Talo edition) with Ameriglo sights. I need to shoot it a little more before I carry it, but I haven't found anything about it that I want to change.
Typically, the aftermarket does a good job of finding ways to arguably improve factory Glocks. Glock watches what happens and integrates some of these features into the following generations. Aside from the Gadget, it's not obvious to me how the Gen5 pistols can be made better.
Sent from my Moto G Play using Tapatalk