Okay so I just went back and scanned the stats.
Niko actually does decent on stage, but has more fall off performances than I remember, but nothing too crazy when compared to everyone else. Of course we're comparing AWP to rifle for most of those, but it is what it is. Honestly G2 though overall and even his time spent on other teams were all worse compositions than even a weaker Navi or Vita IMO. Like just because he was put on a team with a few fading super stars who weren't playing anymore I don't think you can claim the team was actually better T2 and maybe even T3.
I actually don't think of Niko as a team player. I think most of what G2 does is have 5 individuals doing the best they can and hope that is enough. He might play a bit with his team but the majority of his gameplay is trying to find the solo pickoff.
But since I looked though all of it I will concede that he isn't as consistent as I thought he was in the past, but that I don't really think he chokes playoffs as hard as the rest of his team does.