"I will say that the Glock didn't innovate any single feature (except the trigger dingus - not something too many people value) but they did mix the features together for the first time and set the trend for modern pistol designs."
Glock didn't even originate the trigger dingus which is a design feature that predates World War II with the J. P. Sauer & Sohn Model 1930 Berhorden. It has the little trigger dingus serving the same purpose. The feature has been around since... well 1930 or longer than Glock.
Cool link showing photos of a nice example of the Model 1930 Berhorden.
The National Firearms Museum: Sauer Model 1930 Berhorden pistol
The Glock is an almagamation of designs from bygone times, all done up in plastic, and very important for its impact on the thinking of the pistol shooting world.
Personally I abhore them but the Glock has to be given credit where credit is due.