Audio engineers want accuracy. A ruler flat response is ideal. They don't want "enhanced" bass or a "sweetened" high end. If reverb isn't in the recording, they don't want it added by their headphones.
Dave Rat has done a series of blog posts and videos where he looks for the best headphones for live sound engineers. His focus is on live sound, but most of the principles apply in the studio setting too. The series is about five years old now, but the theory is still sound.