There's really nothing to add that's already been said. Lets put aside all the fetish art and sexually explicit imagery because that can be any site you go to for artwork.

1) Piss poor moderation if it's even existent at all: This allows several bad actors to get away with harassment and other forms of cyberbullying. It doesn't help when people have discriminating views and often have fragile egos when it comes to their artwork.
2) Layout sucks, hard to navigate: Way before recent times the navigation wasn't great, but everything was categorized in a way that made sense. Now it's trying too hard to be like instagram.
3) Money matters more than the user. It pushes for you to get a membership to get features that don't even matter let alone get you artwork noticed. Even then, it doesn't matter if you do because it shoves it down your throat to a point where it's going to cost you more money than it's worth and that's far worse than having to pay for an adobe subscription.
4) Lastly, the community is non-existent. Sure you could go to the forums and have some conversations but they won't do you any good given the first point that's highlighted. It's also tough to even build up a following there compared to other sites that are in existence.

The thing is I'm not the only one who had these issues and I'm actually glad that I walked away when I did. I'm not saying that this reflects the entire community, because there are people there who actually make good art. The problem however is when you have a good majority of users who only care about themselves and would rather push you to the point where you're better off going elsewhere.

But it's hard to get noticed when the site has a bias toward users who have either been there for a long time or have more of a professional background experience. It's harder for underground or unknown artists to get a following there and I'd rather go to other sites instead of DeviantArt. Sooner or later Deviant Art is going to lose a lot of it's business with everyone if it doesn't take actions to improve the community more than anything else.

If you want a site to build a following, you're better off going to Newgrounds, ArtStation, Hell even Instagram is more artist friendly than this site.