Personally I would remove the touch pad as its rarely utilised and that would automatically cheapen the cost of the controller. I felt the touch pad was more for Vita games etc but it didn't seem like it turned out the way it should of. I would keep everything else. DS5 is a solid controller and I would find a way to make the light bar smaller or dim it when playing games it doesn't use. Or simply add a On/Off button. The light reflection on the TV screen when playing horror games in the dark is very annoying.
The touch-pad has some quite useful applications, like unit control in RTS games, and smartphone-like navigation in map screens. The problem is that much like the motion controls, Third parties rarely use these features because it'd give the PS4 version too much advantage over the Xbox One version, and we can't have that now can we? /s. This is why Sony needs to put their foot down, and start forcing developers to use these features where they make sense. No, that doesn't mean mandating touch and waggle gimmicks into every game. But why not insist that Activision add gyro aim options to the next Call of Duty? It's embarrassing that its 2019, and we're still forced to aim with the inferior analog stick in console shooters. Developers have a mouse-like aiming solution right at their fingertips on PlayStation, but nah, let's stick with the same archaic, aim assist and bullet magnetism mechanics that should've died last generation.