Bounties with low allocations don't dump in value, that's why I like joining such bounty projects but its sure that the reward will be low, there are other few cases too that the project can 2x or 3x easily
See it is not necessarily true that the low allocation of the bounty saves the project from its hunters dumping their tokens. The hunters joined because they wanted to dump and make some quick cash. This is the side effect of giving bounties for every project and not being exclusive to few projects which showed their generosity for the community in this way of getting a bounty pool.
That may be one of the reasons but truth is that bounty hunting days are over. If you want to earn some altcoins buy them - put in your cash and buy them. You can always go for bitcoin paying campaigns and that is what people should focus on more on.