Haha ohhhh kay wow this is amazing
As you can see it seems they did have to scale down Wailord a bit for following you to work. Makes sense.
They do an interesting thing with following pokemon: they follow you relative to their actual speeds! So corviknight is able to stick with you very easily. It'll give a little space and then follow right behind. Wailord, on the other hand, is a slow moving pokemon. He trails behind you as you move on ahead. I think if you get too far ahead he'll warp back to you.
I think some people called this half assed but I really love it, its cute.
Wailord is also, perhaps, too big, sometimes depending on the camera angle and what's going on the model will "pop" out of existence. Not like how it does in HGSS, just the usual model popin issue the game has. honestly? Perfectly understandable.