Age might be an issue Thiago has to deal with, which Rodri doesn't, just from a physical aspect. Rodri was like a dear in headlights for long portions of his early PL career and while Thiago will likely be better next year (or not be as bad, I think would be more accurate), I think he'll still struggle with the pace due to his declining physical attributes. That is unless Klopp completely overhauls his system, but I don't think he has the right personnel to switch to a system that will totally suit Thiago, and if he were to go down that road, that poses a whole lot of other issues.