I always liked old slashdot. The meta moderation system applied to reddit like moderators would be an interesting experiment allowing the community to police the moderators...

You have to manage this carefully. It makes sense to give regulars more power. Take this little community here: You have some power users who have been here for years, who are posting high quality links and high quality posts with many upvotes. It makes sense to give them more upvoting power than some random new account from some new instance. This is something that reddit is struggling with and I suspect Lemmy is too or will be: It's easy to setup a bot network of a few hundreds or thousands of accounts. They do not need to post, simply up- or downvoting certain topics will help to drown certain stories. The best stories here will gain ~600 upvotes, so just a few hundred accounts will give you the ability to manipulate what is showing up. And favoring older, highly-upvotes accounts is a way to prevent this.

(if you take a look at reddit, you'll see where this is going: Old account get sold. There are karma-farming bots. Some communities are simply banning new accounts without Karma from posting in order to get the spam in check. Others are invite only)