I really like
@gbear605's suggestions to actually write out the unwritten rules (e.g. to make an announcement post quoting your plan if you edit that plan) and to describe salient points/differences between plans being voted on.
I also like
@Dictator4Hire's suggestion to make the methods section of a plan more comprehensible. Especially if combined with shorter-term action plans this might be helpful for everyone involved, since it makes both writing and critiquing plans easier and presumably will be easier for QMs to interpret.
Prettying up the second post (fan art) and adding total-beginner explanations of things to be more inviting?
Varying degree-of-complexity summaries at both the top of the Player Doc and Wiki (possibly with similarly complex mechanics / voting explanations?)
Thread advertising: there are
artists who could be commissioned to make sweet banners and raise awareness / encourage people to participate (what to put on them? Seal designs? Hazou's face? Group sketch?)
Tags: don't know how many people actually use them to find quests, but ours are pretty sparse. Even just having things like "ninja" in addition to "Naruto" might help, I dunno.
Reddit recruitment: player-recruitment/FAQ thread? Just to let people know the QMs/community really love it when new people join and we'll be nice and give them cookies? maybe people who are usually lurkers would be willing to chime in here - how many of you are from the subreddit?
Making the wiki and tvtropes pages much more comprehensive potentially also useful