I think this would be a significant Quality of Life upgrade
(you can vote at top of thread)
Yes, would vote, but am off votes.
And as additional feature jump to the next free slot, when a hero was put in. I often put another in the same slot, since this slot will stay active and then one has to scroll through the bench again.
Not sure it matters too much. You still have to click the slots to put a new hero in so this really just adds another click if used. Unless you are looking at swapping troops - then this makes a difference.