I mean, I think it would be nice if 'Castrum Meridianum' and 'The Praetorium' were turned into regular 4 mans, with the final fight against 'Ultima Weapon' being a trial, follows the pattern of the following 3 expansions then (not at the end of Endwalker yet so not sure how that one does it.)

Most of the cutscenes in Meridianum could be replaced with NPCs running around in instance. Praetorium is a little tougher to tidy up, but most of Gaius speech at least could take place after the new final fight but before the Ultima trial.

All that though, while nice and neat and tidy, isn't really necessary.