With the rampancy of signature campaigns, the tendency for participants to type to meet quota (even if they don’t really make sense is high). This is why I think that a demotion (or demerit) button is appropriate. This would mitigate the preponderance of the disappointment in reading posts from some so-ranked Legendary sounding like it’s from a 12-year old.
The merit system is enough to handle all the issues raised and it's handling them. The difficulty in ranking up will enable us not to have incompetent legendaries in the future. If there were others promoted to legendary before the merit system, they should enjoy it. I have read people proposed that all airdropped merits be retrieved, I don't support that, that is part of the forum history and shouldn't be distorted.
If accounts changed hands, it's also part of the system as no system is without a flaw. Besides, I do not think there are still good accounts without tags that are still up for sell these days. So, those few ones will extinct with time.