Just got a second 43x while I was looking at a Glock 19. I decided I have been carrying a Walther PPS or my G43x IWB most days right now that I had to get a second. Then I traded a pistol I had not shot in 4 years for a Glock 48. I think I am good on pistols. I really see no need to go away from a Glock 19, Glock 43x/48, or Walther PPS. I prefer the G43x but the PPS with 6 round mag makes for a eaiser gun to concel. The nano is even smaller.
I think for someone who is just getting into the small Glocks, a G43 and G48 would provide the flexibility to cover all those bases since you have 4 possible combinations just by swapping the slides. And when the 15rd flush fit mags for the 43x and 48 hit the market, assuming they are reliable, the G19 market will take somewhat of a hit.