It would be a lot easier to deploy troops if, once all units of a certain troop are deployed, their icon disappears from the queue at the bottom of the screen. Currently they get grayed out, but disappearing altogether would be much more beneficial, especially when you have a large variety in your troop composition.
I think that it would hardly be beneficial, it would be more negative. I would probably lose an attack or accidently activate a heros ability when I did not want to. Plus, I usually use the grayed out icon to not have a troop selected, so I don't accidentally deploy a troop/spell.