Do only some badges have rewards? I completed the final badge for killing troggies and have made it pretty high into the cutthroat killing badges and don't seem to be getting anything. Is it a bug? Just not implemented yet? By design?
Not all badges give rewards. Only a few do actually. I got one while completing the main story (you will get it too). Keep moving forward, earn badges as you see fit, and you are bound to find some with rewards =D
What most of the badges seem to do is unlock the ability to buy Companions in the Crown Shop. So far, I have seen only 2 badges that have rewards associated with them and I'm a level 22 Privateer in Cool Ranch.