Bounty restrictions can fix few problems facing project price drop after listed on exchange,
1) if any dev want to avoid dumpers then they must limit bounty participants, the limit the participants they better ,if a bounty only request 300 participants at highest and the 300 became a dumper it won't hurt ,unlike 2000+ participants
I think this is not favorable to a project since only a few people would promote the project and the probability of it to be successful will also be low. Locking the tokens for bounty hunters would be a good idea if dumping is the problem here but it is not in all cases that bounty hunters were the one dumping.