Considering N4 lets it squeeze through 27.5mm gaps and removed the 30% minimum coverage for cover, I think your main result is a bunch of pissed off Yu Jing players who have to rebase their TAG onto a base too small for the model to properly fit.
You mean like a new miniature? Or a new TAG altogether? If a new miniature, they'd still need to change the profile to fit a different base size. Which would still invalidate everyone that already has an O-Yoroi (apart from a few with an N2 version that never rebased) If a new TAG, a theoretical Gusoku or KeikÅ, why would they keep the same profile apart from Silhouette? Instead of an up-gunned or up-armoured TAG, or something with more mobility?
Just a new miniature. I dont think still calling it Oyoroi and having an even mildly different kit from the original would go over well with fans at all. Also, since JSA is notoriously a short range faction, I believe its TAG should more easily be able to take total cover during deployment, especially since it lacks the standard EXP/DA ARO. S6 is just that much easier to do so. Also also, I would love for an Oni themed TAG with similar design to the Daiyokai (hat with horns, mechanical oni face, same type of armor and flag on back complete with EXP Kanabo).