>>29919967Processing power aside, the 3DS screens are pretty small, so the camera would have to zoom out a ton to let the player see anything but Wailord, and that would make it hard to distinguish anything else on the field. Visibility is more important than size accuracy.
The Trainers are also too close to each other to really allow a full-sized Wailord without most of Wailord's body being behind its Trainer, and that goes double for multiple Wailord.
