I picked up my G30S today and really like it. So much easier to operate than my Springfield XDS, but then again, it is a little bigger than the XDS too. But I think the 30S will be my new go to EDC once I have put it through its paces. But, while looking at the way the 30S is put together today, it struck me that Glock's ability to use the slim slide on this pistol provides a possible proof of concept that could be the genesis of coming improvements on other models. If Glock can engineer the recoil spring assembly to allow reduced slide mass on this pistol then they should be able to use those same principles to create the following: G21S--I have considered a G21SF for some time now but always opted against it due to bulk and weight. But if Glock could engineer a 21 that used the slim slide, then I would have less reason not to buy one and would probably get one to accompany my 30S; G30SL--(slim long) they could make an intermediate size 45 between the 30 and 21 using the same slide as the 30S, but giving it a little longer grip so that you could maybe have one more round, use flush fit magazines, and get all your fingers on the actual frame of the gun rather than using the pinky on magazine extension. It wouldn't be able to use G30 9 round magazines to make the hight profile down for concealability, but we really don't have that option now anyway since I cant remember the last time I saw a 9 round G30 mag; G37S--I always liked the idea Glock had in introducing the .45 G.A.P. so shooters with smaller hands, or just those preferring a smaller grip, could have a .45. But I was immediately turned off when I saw the bulbous thick slide overhanging the sides of the frame, necessitating the use of the extended slide release, making it harder to find holsters, heavier, etc. But now with Gen4 recoil spring assemblies, they could slim those G37 slides down to create the G37S which would then have the same profile and unloaded weight as the G17/22, and would be able to find holsters. I think that would finally bring the G.A.P. cartridge into true relevance for use with LEO's and Civilians who want a .45 but not the hefty G21; G38S--Using the same principle applied in the G37S concept above, shooters with smaller hands, or just preferring a smaller grip, could have a .45 in a package identical in size to the G19/23 but with a wider variety of holsters available; I am not saying any of this is actually going to happen, because I know there are a lot of models out there that everyone wants that Glock still hasn't brought out. All I'm saying is that the 30S proves that a slimmer slide could be adapted to other models currently in Glock's lineup to freshen them up a bit and really give them a better chance to compete. Wishful thinking, but hey, you never know.