What If...
1. We stop the bounty campaigns signature campaign that pays token so the spammers will just focus on doing twitter/fb reports to a certain thread (which is the thread of the bounty they're enrolled) and an alternative is to hire a manager (Good manager) that will hold a signature campaign that pays Btc, Eth, etc. and put it to services section.
2. Implement a rule that in the forum and to bounty managers/projects that accept only a participants that has a merit for example.
Jr. Members - Needs 20 Merits
Members - Needs 30 Merits
And so on...
Negative effect:
1. Many of the shitposters will just going to send merits using their alt accounts.
2. Merit begging.
3. Merit Selling/Buying.
Positive effect:
1. The traffic will be the same.
2. The Spam will decrease.
Hey people I didn't say that all of what I've said is right, we're not sure. This is just all my Idea and I just want it to share.
I think your suggestion of stopping Bounty signature campaigns are too far to be possible.
FIRST, The ICOs, Platforms, and Crypto-related Projects do also needs the help of signature campaign as an additional way to promote their ICOs because some users here in Bitcointalk also onto investing on a certain ICO or Project they can see in users' signature. Also, not all users in here doesn't qualify in Twitter and/or Facebook campaigns of a project's Bounty.
SECOND, Bounty managers are just managers and not the bounty makers/investors/and especially they aren't the ones to pay. They just manage on who's participating and the auditors of participants' rewards. So suggesting certain currencies to be paid in their signature campaign is just them giving rewards on signature users without their ICO being successful in the long run.
And lastly, Merits nowadays are hard to gain even if you post with your maximum effort because of dozens of users also replying on a certain thread you replied. AND Spam will never decrease unless the all users are DISCIPLINED.
This merit system is enough to discipline shitposters and spammers for them to remain on their rank.