According to comments from the devs, it is intended that every Battleborn has the same 30% sprint speed modifier. A comparison of Mellka and Caldarius shows that this cannot possibly be true.
Forgive my girlfriend (the Caldy) if she looks at all wonky in her movements, such as when she twice slightly nudges a wall. She doesn’t play much, and as you can see, the outcome is pretty cut-and-dry.
edit: just to be crystal clear, the first race is without sprinting (running, I guess?), and the second is sprinting.