We're in the middle of a major re-write of the entire flagging system. As part of this, we're re-thinking how flag weight (and thus "hell bans") work. Anna & I have been discussing this for a while - here's what we're looking at doing instead:
Only look at folks who cast at least 10 flags a week. There isn't much point in doing much to knock the priority of flags from people who rarely flag anything.
If at least 10% of your flags from the past week were declined, you'll get a little warning next time you go to flag something... Along with a link to your flag history so you can see exactly where the problems arose.
If at least 25% of your flags from the past week were declined, you're blocked from flagging anything. Depending on when and how those declined flags were cast, this block could last for as little as a day, and won't ever be longer than a week.
Over time, the flag system has evolved from a rather opaque "I saw a problem, please do something" system into a way for everyone to work hand-in-hand with the elected moderators. This must necessarily include feedback on how you're - closing that feedback loop should help our more prolific flaggers to become better at flagging, and reduce noise for the moderator teams.