Colosseum and XD style graphic could do the same thing if they wanted. They just didn't.
Colosseum and XD also arguably have worse graphics with those outdated, ported up N64 models. I like the cel-shading more, but I do wish we had Colosseum proportions in the overworld and style battle scenes overall.
You know how in games, the designers take a 2D image and give it a 3D-looking image to make it SEEM like it's 3D? Like those giant balls in Mario 64, or the Bob-ombs?
In Colosseum, that's what they did with Jumpluff, and it confirmed for me they just ported the N64 models over. The main thing that gave it away was the fact that the 2D image casted a shadow. The shadow was perfectly square. A square shadow underneath a supposedly round, fluffy ball. XD fixed that, at least.