This is not new and has been the case since ARR.

If you are a PLD MT that is staying in ShO, your party would be better off with your WAR MTing and the PLD OTing in SwO. But, if your PLD can MT with high SwO up-time then they are a better choice to MT than a WAR.

The same goes for DRK. If you are a DRK MT that is staying in Grit, your party would be better off with your WAR MTing. But, if you can manage the fight Gritless, the DRK is the better choice to MT.