While investigating a site issue, Tim found that a single editor was making 4 edits/second, which was causing impact to the site.
We rate limit edits for anons and new users (8 edits/min), but established users are not throttled. Should users have a limit (something pretty high, like 60 edits/min)? This is significantly more than the guideline for bots (https://meta.wikimedia.org/wiki/Bot_policy#Edit_throttle_and_peak_hours), but would ensure that a legitimate user isn't blocked when editing quickly.