The Xbox controller. Though there have only been 3 generations of Xbox and 4 base controller models, you could arguably trace it's roots all the way back to the Sega Saturn, and by proxy all the way back to the Sega Master System.
The controller has evolved a ton, and though many, myself included, refer to the Xbox One controller as the GOAT and standard go to for PC controllers thanks to its build quality and layout, outside of ergonomics, there haven't been too many innovations from the 360 model.
Does a controller need much more?
2 triggers, 2 bumpers, 2 sticks, 4 face, 1 D pad, 1 guide, 1 start and 1 select.
The obvious feature is some sort of screenshot or record button. The way it's handled right now for Xbox One is less than optimal, requiring you to use the Xbox guide. In Single player games with suspend/resume, this isn't an issue, but in Multiplayer games, it can potentially cost you a win.
Personally, one minor thing that I'd love to see improved is controller syncing. The sync button on both the 360 and One pads in combination with the actual process is kind of garbage and takes forever. I'd like to see an implementation similar to the Nintendo Switch in this regard.
Thoughts?