I do think heal requirements need to be given more thought for sure, looking at the incoming damage in 'Extremes' such as Zodiark is eye opening really, but it's just one piece in the puzzle really.
To really stress the point, even as a White Mage, the healer with the weakest oGCD kit, we've hit a point where outside of extreme situations where other people are at fault, pressing glare is almost never the wrong answer. There's just so little thought required for the bulk of the game outside of certain Savage and Extreme turns.
Feather style charges that we can rapidly overcap on, thundercloud procs that have a short window to be activated and used, even stricter resource management across the board, buffs that are dependant on positionals. There's lots of different ways outside of simple rotations to add depth and engagement to those 150+ button presses per duty. This is where SE really need to put some effort in IMO.