Remove of airdropped merits will make old Senior Members, Hero Members and Legendary members feel paranoid,
For example every Legendary member could only get 900 merits and become Hero member, and every Hero member 400 merits. Maybe this is not best idea, but it is much better then take all airdropped merits.
I'll consider it one of the best ideas as, it's preferable than removing all airdrop merit. The old era-member who were quality contributors won't find it difficult to earn merit but the spammers will get trapped and they'll be the ones disturbing the forum with complains. This suggestion if implemented will also turnout to be an advantage to the airdropped users as, they won't be overlooked by campaigns managers when applying for a slots like they're currently been overlooked.
Here's another suggestion, all airdropped merit stays but smerits declays. Now when a user, get certain amount of good report against them for spamming, they get punished by removing some airdropped merit. Could be 15 merits per every 5 good report against them. This way, only the spammers get affected. The report used for this punishment has to be strictly spam related.