the number of level 50 quests after the Praetorium and before Heavenward are a result of how the game re-released.

also the way post end of the main story work. yes it can seem a lot.

however, post Shadowbringers there are 51.

Post Heavensward, 40ish

Post Stormblood, 40

yes, it seems like a bit of a slog, but in a lot of ways, they are just setting things up. might work better if they halved the experience, but then leveling would seem slow. its a hard one to fix satisfactorily to be fair. they did streamline it a bit recently but it is a bit slower seeming than everything else since there are a lot of bits to move into place. after Heavenward to present though... it doesnt seem like there are enough quests...