Before you read on, note that I'm a legacy player. The highest teir that I can attain is 12, I don't know if that's changed with ROI.
[b]Your teir is your bars of intellect, discipline, and strength added up.[/b]
I've not seen very many higher teir players, so I was wondering about B.net.
-
They "nerfed" all the armor stats prior to RoI making it necessary to level them up to or near 400 light to get their "true" max stats back. As such, the max tier didn't change much from TTK to RoI unless you count the Felwinter artifact but that negates your super so it's kind of pointless.