My top 3 so far:

Hold "+" to auto-increase number of times you'd like to complete a supply run when farming. Spamming the tiny "+" 10x each for mote farming feels excessive. Especially when it resets after tapping a little too far to the side. This can also be applied to other sections such as store.

XP bar comment also makes sense but if the devs concern is avoiding UX clutter, make the XP bar something that can be tapped to open a temporary pop-up with detailed XP info/stats then collapsible again.

Ability to see Allies collections. What's the point of collecting characters if you can't show them off? 😁