A feat should make sense no matter what, not just because a standard says that it has to. Trying to turn a slow-moving attack into a supersonic KE-kick is obviously just abusing the KE rules to make nothing into something, and we have clearly set a precedent that KE feats should be put under particular scrutiny precisely because it's so easy to get a random motion into high tiers. I would point to that same recent Naruto thread that was trying to give characters Class P for moving a sword during a Rel+ feat - we rejected that not because it explicitly broke any of our standards but because it was obviously not actually a real feat, these standards are just meant to outline that, they won't cover every edge case.
This is obviously a lower tier but the principle is similar. The fact that this is so abstract and requires several assumptions (like Mettaton creating giant legs rather than just kicking, the electricity actually being X speed, the KE being properly represented or even intended, the electricity being real, the legs actually moving at speeds comparable to it, hell even a lot of battle box/UT standard interpretations like how you interpret the Soul taking damage, or its size being fine to pixel scale things...) to all be correct just to make sense pretty clearly outlines that it's not good to use - some of these assumptions may be fine on their own but all things together there's too many points of failure for this to be the leading AP feat for a verse.