I feel like Xavi's obsession with playing as much as he used to + the purchase of Fabregas could be what forces out Thiago.
My ideal scenario would be:
1. Reduce Xavi's minutes by a good amount and give them to Thiago. By this I mean all copa matches, 40 to 50% of La Liga matches, and any Champions League group stage matches where the group is already won should be started by Thiago. He should also be used as a sub a bit more often.
2. Alternate Cesc with Iniesta to keep them both fresh.
3. Give Cesc starts at False 9 in copa matches(except the last few rounds if we face tough opponents) and sub him on for Messi to rest Messi in matches that are already won. By this I mean at like the 65th or 70th minute. Not like Tito's 87th minute subs.
With all these adjustments, everyone is rested and gets a good amount of minutes. Xavi is fresh, Thiago develops, Cesc gets minutes, Iniesta and Messi are fresh.