When I am looking for a bounty I look for projects, that have a HUGE community behind them. I research the team, the devs, and even the bounty manager. You can also find some pretty decent bounties on bountyhive, but there is still always the possibility of it being a scam coin. You are going to have that issue no matter where you go. The best advice I could give is research, RESEARCH! RESEARCH!!!!
Youe are right, we just really need to make more research about the campaign. For me I am looking for a big community participation and an active teams with good website template. Aside from that there are still a lot of factor to consider in choosing the right bounty campaign.