When I learn what mature means, I'll reply to that. In terms of content and subject matter, its grit is on part with DS9. We haven't seen Starfleet officers walking around with necklaces made from trophies cut from their enemies' bodies, DS9 still has that. It has had allusion to prison rape so it's about on par with other Trek shows that have done rape, ghost-rape, mind-meld rape, etc. Insane brilliant captain possibly in over his head, wait that's been done so many times its a trope, only this time he's a wonderfully written character. And let's see, a character who went through loss in war, torturous pain and then weeks trying to recover mentally hiding away among humans.. wait.. holy crap.. Voq is Nog! Id say right now Discovery is on par with DS9 for grit, if they were both sandpaper.