For me, it wasn't so much the diversity, it was that everyone seemed to be struggling with their diverse identity. It's the 23rd century, people should not be uncomfortable with their identities anymore, ESPECIALLY the crew of an advanced space ship. It just seems that rather than a professional crew that we see in every other Star Trek show, they decided to pack this one with a bunch of high schoolers struggling to figure out who they are. For fuck sakes, the ship itself starts having an identity crisis at one point.