>>56891529https://www.youtube.com/watch?v=RK95IUuXs74The terrain change is one of the best ideas in the anime, and organically adapts how and when to use Pokemon adapted to aquatic, aerial, or arboreal battles.
Even Smash paid homage to that mechanic, the question is why haven't the main games implemented it? In the first generations you didn't need big resources, just change the background with a png and implement secondary effects, like an aquatic terrain is like having Rain at all times, Harsh sunlight with a desert terrain or a tree terrain decreases the speed of large Pokemon and increases that of small Pokemon.