That's kind of an apples and oranges comparison, though, right? The entire point of the Pro is to massively enhance games when supported. The One S boost is not a big deal and isn't even discussed by marketing material for that reason.
I haven't tested that many games on my own system, to be honest, but I did notice improvements in a number of them. Obviously ROTTR runs better but Halo 5 seems to maintain a higher resolution more often, Gears Ultimate has less slowdown, Gears 4 holds 1080p almost all the time on One S but seems to dip below that on a stock system and Ori seemed a bit smoother (it was already mostly 60 but a couple spots would dip - they were fine when I replayed it on the S).
Beyond that, though, I haven't really tested many other games and anything else I tested was basically the same. I don't think it should be a selling point, though, since it seems quite minor and not something most people would notice or care about.
Clearly, when games support the Pro, you're going to see much more significant improvements and most games are awesome on there. Going forward, Pro support should hopefully be pretty standard.
It is odd that people use the One S as a comparison point against the Pro, though, since they are fundamentally different.