I disagree. Looking at this art contest, each depiction has a Kanohi unique to it, and created to suit only that depiction. Throwing in a different style of mask will most often ruin the depiction.
Furthermore, even if the goal is to make a Kanohi that fits with the winning depiction, it may still clash with the armor. Look at @Risebell ‘s and @Mister-N ‘s entries. The mask is a part of the armor, in a way. A different mask would not work as well.
Very well presented. I’m still not sure I agree with merging the two contests, but you’ve provided some very good points that have definitely made me question my position.
I don’t think it’s a bad idea at all to have some sort of separate, ongoing poll to allow other artists who don’t win these contests to provide their own interpretation of the winning art. Take, for example, the Certavus page on BS01, which contains multiple forms of art, all interpreted from the winning MOC.
It might be better, in that case, for the admins of BS01 to consider opening up a thread for art submissions throughout the community, for the purpose of beefing up the galleries of characters that have only a few images. It could be a nice way to have some sort of ongoing contribution based off of the winning contestants.