One of the features of Glock has been the ability to use the same or larger capacity mags of one caliber in another Glock of that caliber.
I can use my 17rd-sized mags from my G17 in my 10rd-sized G26 -- both 9mm. Yeah, the G17 is only 10 rds for HI compliance, but that's just a detail.

So, being able to fit a 17 or 15 rd mag in a pistol that came with a standard 10 rd capacity is a possible selling point.
And, if you splurge for a 30rd mag, it'll fit all of your double-stack Glocks of the same caliber.
Now, with the "innovation" of a single-stack Glock mag, the interchangeability of mags is less if you buy single-stack Glocks and double-stack.
Let's say you're in a competition and one of your mags fails, leaving you with one too few to make it through each stage. Chances are good you can borrow a mag from another competitor.
In a pinch or SHTF scenario, if you need another mag, there's a better chance of finding a fresh mag that works in your pistol if you have a Glock 9mm -- whether it's from a Cop, another civilian or in someone's stash you happen upon. Kind of an odd "feature" to look at, but when you have the most popular caliber of the most popular brand, you have a much better chance of having the parts and accessories you need.
Then there's the cost. Glock mags are generally half what my metal Sig and 1911 mags usually cost.
The drop-safety system of the Glock is a definite plus.
Being a DAO (striker-fired) firearm is a bonus for the Glock, too, particularly in competitions. The time to get that first shot off can be the difference between a better score than another shooter, or a worse one.
The first time I ran the MPPL course, I used my Sig P226 which required I fire the first round DA with the hammer forward, and each subsequent round was SA. The DA trigger pull was much heavier than the SA pulls afterward -- I'd say about twice as heavy.
The second time at MPPL, I used my Glock 17. I found the simplicity of the Glock to be more of an advantage over the Sig. Each trigger pull was identical from the first to the last. Makes a difference when trying to shoot as fast and accurately as possible.
Yes, more striker-fired pistols have come/are coming to market, but this addresses the question asked about Glock fans and innovations. There are more to choose from now (like my favorite: P320).
Anyway, just a few thoughts. YMMV. I'm seriously thinking of divesting myself of all things Glock in favor of my Sig collection and various revolvers. I'm getting to that point where I'm more about minimizing, and the P320 offers versatility of size and caliber without having to own several firearms -- just the X-Change kits. I am becoming less convinced that I'll ever be required to shoot a bad guy in the head as he holds a hostage in front of him using a Glock that I don't have a lot of practice using.
