The big problem with AST’s card system in Heavensward and Stormblood was that some cards were more useful than others. Specifically - Bole was useless due to it being inconsistent mitigation with a trap Royal Road effect (1.5x for 1 card instead of just playing 2 cards)
If the cards were bag randomised instead (Where you got all 6 in a random order, rather than 1 of 6 every time) then each card wouldn’t have to compete with each other, as you were guaranteed to get all of them over the 3 minute course.