For me, the positive 5.X change is probably the involvement of cross-sect actions. They've been interesting (thematically or otherwise), but the efficacy of the cross-sect actions are poor.

The changes to the card system is double-edged in my eyes. Stacking seals for Divination has been fun. Yet when contextualized by the long cooldown and weak effect, it has quickly transitioned into tedium. It feels bad to commit work to Divination only for it to barely be stronger than +dmg% bonuses available to other jobs that are available with less investment (Devotion, Trick Attack, Brotherhood, Battle Litany). Though I may be misinformed on this point, it also feels useless to deploy a lower level Divination as the bonus is so weak. But it might not be the case if you're aiming to line up raid buffs every X minutes.

There's been nerfs across the board to potencies and cooldowns without (in my eyes) the appropriate strength in the cards and new actions. Although I would like for SQEX to buff AST before savage hits, I don't see how their dev cycle can achieve that.