Been running into this a bit lately with the bigger battles. I can't tell who my characters are and who is fighting who.
Here is how I think this could be easily handled:
Provide a distinct color or brightness contrast when selecting a character so you could clearly see who it is and who they are fighting
Summoned mobs are a different color from the party
Recently had a fight with 10+ NPCs vs my 6 plus 6 more summoned mobs. Trying to see anything on the screen or trying to identify which character was fighting who was pretty much insane.