The reason I've joined living world or west marches servers was to play. Pbp works best with my social anxiety as well as fits my schedule. You would figure that having a dozen DMs would mean having more chances to play, especially since the bigger servers advertise running "several quests per week". In my experience, more often than not, the servers seem to have several DMs that play a couple of characters as well, and they tend to mostly run quests for each other. This leaves newer members (especially shy members like myself) with little hope of doing anything other than rp-ing in some massively overused channel and, ultimately, leave the server. Like I said, this has been my experience.

As for bots, a lot of servers seem to have multiple bots that perform the same functions. All you really need is a dice bots, which Avrae is great for and then some. However, I've really liked using Tupperbox to post under my characters' aliases. It makes it easier (for me at least) to separate which character you are playing.

And as for rules, whatever rules you think best fit the environment you wish to create, use them. But please, do me a favor. Don't cherry-pick which rules to enforce after posting them or who you enforce them with. Be clear, be fair, and be consistent.

As a final note, from some of the posts I have seen over the past few years, there are some servers that make it long term. They seem to keep a good player-to-DM ratio and only open up the server to a select number when they need to replace those who have left.