As was noted here, the devs have made some changes to sorting our hero rosters, and those changes are appreciated. One change in particular that I find especially useful is automatically sorting ineligible heroes to the bottom of the list while selecting teams. You may have observed this working in two places today: class trials and raid tournament defense.
Now that we have this functionality, I would like to propose a third place for this sorting to occur: alliance wars. The UI correctly grays out heroes that I have already used for attack. It would be even better if these used heroes were shuffled to the bottom of my roster. This would give me a better idea of what teams I can still compose for my remaining flags.