I think a lot of the guns designed over the last twenty years or so (going to throw Glock's pistols in here as well, since most of their specific models fall in this time frame and they about exemplified successful innovation in the firearms field when they came out. Sorry HK, but the VP-70 didn't make it. You lose.) have created pretty significant advantages for themselves in design, material finishes, reliability/good-to better combat accuracy, sight options, grip size/features, and capacity/size ratios.
I mean correct me if I'm wrong but there were no guns the size of the FNP-9M that were as reliable as it is, as good a shooter, as high a capacity, as light, capable of having the frame easily and cheaply refurbished by the factory, resist corrosion as well, and had as nice sights all in the same package were there?
I agree with all the posts above too, and if it manages to make it into general production anytime this decade that Boberg pistol will probably be the first really ground-breaking new pistol design in a long time. For the most part the progress we have seen lately is based on input from the shooting community on what works in the real world, driven in large part by competition shooting, the action pistol matches of today are a good bit more helpful in giving manufacturer's input on shooter's practical needs than the old slowfire bullseye competitions.
Also material, manufacturing, and finishing advances have really driven much of the improvement in both new and old designs, it's easier and cheaper today to make a reliable, decently accurate or better, sturdy, and long-lived handgun than it was in the past. CAD probably helped a bunch. CNC probably helped a bunch.
There are quite a few really outstanding classic pistol designs, and revolver designs have stagnated for the most part outside of material and manufacturing advances, but that is probably because they had progressed almost as far as they could forty or fifty years ago. The only way to make them better is to use new materials and new compositions of standard materials that offer better performance in some way, and manufacture them in ways that are more conducive to accuracy and strength. I think all the 12-ounce .357 Magnum revolvers that I never want to shoot with .357 and standard stainless and carbon revolvers that outshoot much "nicer" hand fitted older revolvers show that we are doing that as much as possible.
I think that for the most part, handgun design and manufacture is going to be pretty stagnant for awhile. Yes, new, excellent pistols are being made and will be made, but they are really just the same old operating systems we always had but made in different platforms and shapes, with different features that are better suited to today's shooter, and with better materials and manufacturing processes that allow better and better accuracy without sacrificing reliability. Just like the AICW program the Army had for a new rifle way back, even if we make some small progress here and there I really don't see any game-changing leaps happening until something very drastic happens in the ammunition front.
Wow that kind of writing would probably work wonders in sliding my way through a class without saying much.