If we are removing Harden from the conversation (Paul should be back soon enough), then I would place Kyrie in the 2nd tier with John Wall - so 3rd or 4th. Paul is getting older and his stats will certainly take a hit playing with Harden, IT is still an unknown, and Lowry/Conley/Lillard just seem to be in the next tier below.
I realize I am probably biased because Irving is a C, but age, actual production, and quality of team should also matter in these rankings. I think the more Irving gets used to playing under Stevens, the more clear it will become that he is a 'real' star.