One drawback of this "subs are tags" idea is that it's harder for a sub to develop a unique personality/community because these are now gone, I think: sub rules, custom CSS, user flairs, and automoderator config.

So the unique personality would form around the moderators. Automoderators would have to be bots people setup, though I am thinking that making the system bot resistant would be wise... Custom css could still be done, you could have something like notabug spaces or pages people can make. Sub rules come down to who is your moderator. This is the whole point, you as a reader can choose the rules. It takes most of the power away from mods because they can be just deselected or switched out. I can understand current mods won't like this system because many are power tripping aholes, but making people little dictators over our speech and what we can see is totally antithetical to our society it is beyond a joke.

I mean seriously over on reddit and like you basically have little Kim Jong-uns, Saddam Husseins and now quite literally Xi Jingping who bought the place running it and running over anyone they don't like or merely don't agree with... it's fucked beyond belief.