There is a reason why in the Battle scene, the UI only has your Pokemon with a blue brush stroke, but all other enemy Pokemon have their own HP floating in the scene:
I am speculating that it is because in the game, it is possible for you to battle against multiple Pokemon if the wild Pokemon are very close to you. If they went with the old UI where it shows your enemy Pokemon with the red brush stroke, and you're battling with the same species, the UI may get confusing as to which Pokemon it is that has lower HP.
I am speculating that it is because in the game, it is possible for you to battle against multiple Pokemon if the wild Pokemon are very close to you. If they went with the old UI where it shows your enemy Pokemon with the red brush stroke, and you're battling with the same species, the UI may get confusing as to which Pokemon it is that has lower HP.