Well we did give honorary emblems to those players here on forum, who community voted for being the legend of 2017 etc. in Awards 2017. That's one idea for Awards 2018 - instructor / sage / seer of year 2018. And there will be prizes of course.
Writing a game guide in a contest might take some of the fun out of it. Players need time to put their love and energy to their guides, and a time limit or a prize for the effort may water it down.
Game guide sounds more like a team effort and a topic for lots of discussions on strategies, tribes, and what's actually useful info for players of different levels.
...unless the game guides are similar to the ones in Answers page? Those would be pretty awesome and worthy of a contest!