Good work! I like the fact you decided to go for tiers instead of adding an individual rating to every player which, let's be honest, wouldn't have meant much without proper stats to back it up.
One small suggestion though: In order to add disparity within the tiers, you could add a (+) or a (-) for certain people depending on whether they are closer to the tier below or above them.
Gonna take my example so nobody gets butthurt: You put me in Tier 4 with other players such as Swap, Grozni, Termito, Rastignac, Quinn, Wib, Bocom, Tengou, Husarion and probably many others who are all way better and more impactful than me in matches. Whether they are actually themselves closer to Tier3 is another discussion worth having but it's indisputable I am closer to Tier 5. And it's probably the cases for other players too so I think it would be nice to have it represented in the rankings.
I would make a case for Bocom and Quinn to be worthy of T3 for instance and I believe Erik has been finding a bit of his old level since the CL started. His impact (leading put aside) during the heavy matches was tremendous and he has generally been playing well in the other encounters we had. Obviously, it's easier to formulate an opinion on your own teammates.
Cheers for the effort!