On Halo 1 PC, people with really crap graphics cards would show people with "invisibility" as bright orange glows. So when we played out 8 player local matches, people on the old crappy PC's had a pretty nice advantage
I'm honestly not sure if I care about people having a slight advantage with the PS Pro. Most people who want to game "properly" on the Playstation, will upgrade to the Pro. The majority won't care as long as everything works nicely.
I mean, how many people game with the PS4 on a monitor rather than a TV to reduce input lag? Not many I wager. Those that do, more power to them. I'm equally happy playing split screen online Rocket League or COD. It doesn't make me much worse as a player (I'm terrible at double jump COD anyway).
Seems fair to say either play to have fun, or get the Pro? When it stops being fun, then you've got a problem.