If someone has a lot of karma but a relatively new account it probably means they post comments/articles that are in line with the hivemind, but it's not an indication of quality no?

I agree; it would most likely just amplify the status quo, making already-popular people even more popular.

Aren't green usernames what you are looking for?

Green usernames show who’s new. There’s no similar indicia for who has the longest tenure or greatest karma.

Yeah, that's correct, but it filters out potential bots or spammers, who made an account for the sole purpose of submitting new entries. (I read parents comment this way that he wants to avoid blog spam etc.)