How about Bounty hunters avoid such Bounties.
If you see an overcrowded Bounty, the best you can do is just avoid it.
Instead of doing free marketing for projects here and there.
Also, chat up Bounty admins and suggest ways to make Bounties better
It's easier to suggest ways to make bounty promotions better but that is if the bounty manager is ready to learn, if the bounty manager said no then it's no, nothing can change that, if a bounty program is not satisfying you enough just find another