Gonna talk about SC2 because i'm following esport - and mainly RTS - since a very long time.
What i notice is that keyboards are really not the main equipment pro gamers worry about. Most of the time, their choice is based (forced ?) on sponsorship. I do agree if they would use mechanical keyboards, they would be more comfortable with (days playing, fingers health) BUT these guys have so many APM that their main focus is on APM efficiency, and not improve their speed - because they are already very fast, most of them.
They are certainly more worried about their mouse (weight, shape...) because of fast movements they have to do. Mousepads too. You'll see more pro gamer (or even just sub top players you know, not pro but good) with a "bad" keyboard than bad mouse/mousepad.
I don't believe NKRO is necessary, really. I feel 6KRO is more than enough. On SC2, that's quite simple, you won't press more than 3 keys AT THE SAME TIME (mb 4, but not more). But you will press a lot of keys 0.3 second each, something like that... For FPS, maybe you need more because moving already burns 2 keys, if you jump 1 more, if you wanna change weapon, 1 more and possibly more actions too...