I don't have many PS4 games right now but IMO the touchpad did make a difference in Shadow Fall (control the OWL) or inFAMOUS Second Son (various interactions, drain power sources, etc...)
In both cases it was implemented very fluidly and it's surprisingly reactive so it was not a pain to use it, at least for me.
I now actuality prefer to have some controls mapped on the touchpad so for me it's a worthy addition.
As for the gyros so far no truly interesting implementation IMO. Second Son use them to make graffiti but I found it nice and nothing more.
I would have liked to use the gyros to stabilize aim while sniping in SF, like in KZ 2, but GG didn't do it
The DS4 speaker in Shadow Fall is used well; when audio is played through it felt like I was holding one of the recorders you just found or a walkie-talkie.
In Second Son when you drain a power source a sound comes out of the speaker but the effect it's less interesting IMO.
The Lightbar was not implemented in a meaningful way in any of the games I have played.
In SF GG would have made so that the lightbar flashes more intensely when you get close to a collectible, as it was some sort of "detector", and it would have served a purpuse, they didn't do it.
To me the lightbar is there to work in combo with the PS Camera but I can think of several uses for the lightbar in-game...but that's another story.
So to me the DS4 extra features do add to the experience but must be exploited more creatively and aggressively.
"Good" can come out of them but it's up to the devs...which is probably a self evident truth.