As an individual who did a sizable portion of the framework that ultimately went all unused, here are some takeaways of importance from my perspective.
The first is, is that the public has no idea what it wants. If you tell them something as a designer and they have an issue with it as players, take their input but do not feel obligated to go with it. A massive failure was that
Expanding Horizons caved to the pressure of demands. People wanting it done sooner, topics up faster, rules rewritten their specific way, on and on. Have your plan with the other designers and members of the section staff, unify that plan internally, and go with it; all of you, even if you personally disagree. Making endless concessions will never work and someone will always be dissatisfied.
What would be next in the second is under no circumstances make character creation flexible. This was mostly an issue with
Expanding Horizons because of the fact it was intended to work for free to advanced players and characters of any kind. The leniency was
too lenient and players quickly, as they are want to, began developing characters who were specifically made to be better than those ones before. This comes down to having good rules and just employing them, as well as having at least two approving officials for the character sheets. Continued, if a player has an issue with it, that is their issue, not your own. Do not make a habit of employing special exceptions; if a character is too overpowered, deny it without second guessing until it is change. That creep of power increase will destroy any fantasy that gives the semblance of balance.
Third I would state is to have
all of the ground work done before the threads open. Unlike
Expanding Horizons with a fandom this is far easier, there are entire wikis, movies, books, and the like available. Consolidate those with easy to access links, have a story and plot written out - as in, write the actual overarching plot and implement it from the start and move it along, with or without the players - and have a universal, standardized format for everything and sufficiently pinned and annotated threads. Official posts should look identical across those posting, no matter the section staff member, so players can understand them efficiently. A further recommendation is try to limit the number of starting locations and events so people have a reason to begin interacting with one another.
The fourth and last I would say is to be proactive, in that the threads need the the section staff to actively participate with their own characters and the obvious of those who are non-player characters. They must be reliable, not prone to disappearance or slack, and be consistently active in and out of the game within its section. If someone does disappear, find a comparable or better replacement as soon as possible until they return, at which point the section staff can decide what to do. Do not accept the "They are busy, they will be back soon!" argument.
This all in mind I have touched on what sank the original concept to the dark depths a few times in the past but as a fandom persistent world, many of those issues are resolved by themselves. That leaves these suggestions really as the best I can offer. All in all, best of luck in your endeavors and those participating in the section,
@Star Lord.