“devs too focused on making a game pretty instead of fun” is talking about making the art photorealistic with fancy hair engines and such, when doing so doesn’t add meaningfully to the experience and only serves to needlessly complicate development and inflate the cost.
We can tell that making all these 3D models and animations is a problem for the devs because they’ve said so repeatedly. They’ve even said they can’t have every Pokemon in the same game as a result. Instead of the lovely pixel art of FRLG we have a mish-mash of dead-eyed, poorly-animated cartoons with PSP-quality “realistic” terrain that grate against each other. And for what? Why do 3D when you can only do 3D so poorly?