I am opposed to this idea as currently presented.
Leaving aside my qualms about having more things in Official Library Writing Style (much less of a fan than I once was), I think that this is a bit backwards The GOI page was created in attempt to spur people to ask questions (e.g. "who, precisely, is Dark?") and answer them in interesting ways in the form of new articles.
A contest where (presumably) the entries would be various articles (i.e. things that are designed to answer the questions posed by a hypothetical GOI entry) puts the cart before the horse. There's something about creating a group or entity with the self-conscious intent of creating a group of intrigue that rubs me the wrong way.
I would also oppose a contest to simply create a new GOI entry for an appropriate group. This has more to do with my own personal tastes, though.
New groups and entities are good and can spur creativity, but I think that making the goal "inclusion on the semi-official list of things the Library considers important" will lead to some artificial and less vibrant outcomes.
This is, obviously, just the opinion of one bittervet, but I wanted to put it forward.
(account deleted)