Here is my feedback:
In general I agree with most decisions and rullings made here, but I do have several important disputes and remarks.
1.)
I think the restriction on the parity of metallic armor placement is too restrictive. While having a restriction on the overall amount of metallic colors is a good thing, having it on the armor pieces themselves is too much.
A little variation on the placement can greatly enhance the final visual of both individual and team.
Toa teams are nown to have little variation within themselves without compromising overall cohesive look. Prime examples are Toa Inaka and even Toa Hagah themselves.
This wouldn’t conflict with canon either, as it was never specified that only specific parts of armor were given this color. The only thing(s) we do know/should be specifically mandated are the Masks, shield and spear tip.
It shouldn’t be an issue to put the rest of the metallic armor pieces on other body parts as long as they do not breach certain visual treshold of color representation a.k.a. clash with the visual.
To avoid any abusing of less restrictions, armor could be defined as any piece or conglomerate of pieces, which serve as an add-on to the model and can be removed without disturbing the anatomy and integrity of the model (If you can remove it and the MOC is still a complete and stable humanoid, it is ok).
This would exclude feet, Masks, shields and spear tip - those, while not neccesarily being armor, either can (feet), or must (Mask, shield, spear tip) be in metallic.
2.)
A single shade of metallic armor is not well defined. Is it a absolute to the point of only allowing one concretely lego-termed shade, or does it work in more general terms (Gold, Silver, Copper, Gunmetal, etc.)?
I think the latter would be more beneficial, if only for the color of Silver.
There are several slightly different shades of silver, which ultimately wouldn’t make make much difference, but would be benefcial for creative parts usage.
So I would think that the single shade of metallic could include groups of metallic colors - for example flat silver, pearl silver, metallic silver vs gunmetal.
The minute differences within metallic shade, would be corrected in group artwork (similarly to Artakha contest).
Of course this is not the problem in digital models and art entries.
3.)
If a winning MOC uses 3D-printed or custom masks, I think it would be appropriate to NOT let the artist change their design for the final group shot. As per the practice employed in the standard canon contest format, the creative vision of the MOC (and in this case also art) should be translated to the final team artwork. This is especially true for custom build masks, as there is no clash of interests with BS01, therefore no reason at all to change the mask in the art.
The artists should be obligated to keep the mask design of the individual winning MOCs, and art pieces.
I firmly believe this third point to be a necessity and strongly encourage you to consider it.