Yeah, I noticed that as well. It's like all the other characters are just there to fill space and meet quotas. Morn on DS9 had more character development, and he never had any lines. Definitely not in line with the normal Star Trek formula.
Imagine taking some of the hundreds of disposable "red shirts" that exist on every Star Trek episode and just plugging some of them into nearly every position of the key crew. Furthermore, you don't actually dispose of them and you never bother to build them up so they can get a different shirt. That's pretty much Discovery in a nutshell.