It's a great concept, though it's worth pointing out that there's considerable overlap of moderators between subreddits (a.k.a. powermods).
In effect, you end up with a single system applied across hundreds of subreddits which may-or-may-not be appropriate, and if you happen to earn the ire of a powermod you find yourself banned from all the subreddits they moderate.
Mostly quit Reddit when I realized about 5% of my posts were shadow deleted for holding the wrong opinion.
Mass taggers have historically been abused to ban or shadow-ban users who've posted in "bad" subreddits.
If you argued with someone in r/the Donald, you'd magically be unable to participate in a large swath of unrelated communities. Trying to appeal the bans would often result in you being permanently muted or receiving a snarky response from the mods saying it's your fault for engaging in said 'bad' communities.
There were some grassroots efforts around 2015 to make the mod log public and transparent (so it'd say what was removed, by who, and optionally why), but it was unfortunately opt-in and never gained large adoption.