In the old forum there are very few categories with at least 3 moderators. This applies to well used categories like users:Austria. Therefore I think that having multiple moderators is good but should not be required.
I agree with Tordanik that the OSM Etiquette Guidelines should not be mandatory if the community prefers another set of rules. Especially communities existing in the old forum might be reluctant to combine a software change with a change of rules if they are happy with their existing rules.
Is there an alternative proposal you are thinking about?
The thinking behind is that we want to avoid a single point of failure, avoid bottlenecks or power accumulation/gatekeeping and force collaboration to solve conflict. That’s why 3 seems like a reasonable number, specially if we ask for rotation to get new people involved (once a year maybe?).
Are there any issues you can think of having 3 for certain categories?
List 3 users who can commit to moderate the category. If you find not enough moderators you have to document your failed efforts to find 3 users over a certain time (2-3 months maybe?). At least 1 moderator is mandatory. You should try to find additional moderators if you have less than 3.
This way the creation of a category is not blocked if not enough users are willing to moderate but makes clear that more moderators a strongly desired.
I proposed a minimum of three moderators when starting a category, and keeping at least two on an ongoing basis.
If a category isn’t attracting enough people to find multiple moderators, then how likely is it that it’s attracting enough posts to need its own category? We want to avoid the situation where we end up with categories with no activity.
Also important to note that the discourse moderation tools make the task very easy and we also have a few admins with global moderation rights that can support if things go wild in a specific category.
I am personally an administrator on the French forum based on Discourse. There are almost no moderation and administration tasks for a year. We’ve made some small adjustments to the settings to make the rules a little more flexible, but that’s it.