I suspect 30 is too large for the queue in its current state. I understand you mass-invite people to fill games, but the replacement issue and its impact across the site is a big deal. Even in a 30-player game there could easily be upwards of 10 game days and even if you get a large number of people to replace in in advance, the amount of churn of players you'd likely get would make it hard to imagine the game having much integrity beyond a certain point. IMO slow-paced forum mafia simply isn't designed for very large player counts.
Regarding some of the normalcy suggestions; additional third party alignments and group actions both sound to me like theme mechanics. Yes, the definition of what is normal has changed and will change over time, but that doesn't mean there shouldn't be limits. Other third parties aren't normal because of the reasons NK15 and Dwlee pointed out, mostly because adding complex motivations that players need to understand in order to read and sort people add a kind of complexity that is above and different from what exists in normal games now; it fundamentally makes them different. There's a reason that many players historically would prefer that even multiball be publicly announced, because it changes the game fundamentally and there are players who want to play closed setups without those kinds of considerations.
Neighborhood actions sound to me like a theme mechanic rather than a normal one for various reasons. They're not a bad idea (I think that kind of thing has been done in the past, maybe even in team mafia) but they're not normal. First and more apparent, they viscerally feel like a theme mechanic (which is I think why Cook immediately suggested the theme queue) because they add new mechanics/considerations/complexity. But second and more strong of an objection is that they would add significant mechanical burden; there are a lot of interactions here that players would need to understand, which is a burden on both mods and players, but also on even the details of the design. How would a neighobrhood action interact with various other roles? If the neighborhood action is to cop, do they all show as having guns to a gunsmith? If there's a backup cop would they become a cop when one of the neighbors dies? Do the neighborhood members vote on both who takes the action, and who they target? What if they agree on who to target but not who to take the action? It's not necessarily that the answer to these questions is
hard
to design around, but the fact that they exist adds a lot of rules overhead, and normal games are supposed to be approachable for new players in such a way that they don't have to understand intricate mechanics in order to play the game at a level playing field. This is why e.g. compulsive was really hard to add effectively.
All this said, the queue is definitely overdue for an update, but I don't agree that adding entire new mechanisms is of benefit to the queue when games with those mechanisms can be run in the theme queue.