The butt is not a large portion of pants and Mechagnomes only have "under pants" and any "pouches". So again your elimination isn't based on existing models and what does or does not show. It wouldn't look weird at all. All of the armor now isn't tailor made and we have different leg shapes and angles. The only reason why things will look weird is because Blizzard gave them extra parts that would clip through.
Also the whole tail issue ignores how Chest and Tabard slots would have the tail clip through. So your own argument doesn't even match what you say won't look weird. Strange, right?