The way I see it, the double-contest solves a problem that I would call "contest bias."By holding a MOC contest for X, you will end up with a canon MOC for X no matter what. But the MOC that is good relative to the other submissions might not be that good in absolute terms, and it might be better to wait a while for someone to come up with a better MOC. Plus, as @Gonel said, there might be designs that are divisive. I wasn’t thinking of assigning different tiers of canonicity, though.
As for 3D models, maybe the rule should be that you only need to open-source the design IF you win, which would encourage people to submit designs but still hold on to the rights in case they don’t win. @Gonel’s point number 1 is also valid.
@Mesonak In my view, the purpose of the second poll would be to decide whether the community agrees that the winner of the first contest is good enough to become canon, not to decide whether it conforms to canon. Ideally, only canon-compatible models would be entered into (much less win) the first contest.
Do not double post. -Eljay