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
2) devs should forget bounty when still on ICO ,allow bounties after your project finished ICO successfully and make your project is doing great before allowing bounty
This are just ideas ,if you have anything better please drop on here and let's share.
I will only comment on number two of they will not allow bounty, then the ICO will not likely succeed, in the first place this is why they launch a bounty campaign, to reach as many people and investors what we mean is awareness, very very few ICO succeed without bounty hunters.