Green is not a creative colour. I'm kidding, I'm kidding... I just don't enjoy the green. It's very very dim to me. It's the colour for intellect, generally, but... Deviantart is, obviously, AN ART SITE!! I'd maybe prefer if each individual could change how they see Deviantart. This shouldn't be too hard, really.
I would prefer if we could customize it. If you just do it your selves and asked this everytime, you'd never get a full 100% yes. So yes you should find away for wither us to customize the there or use our own pics.
How about we could change it, but the default was green? Maybe we could upload art to use as a background for our profiles and art that was a simple pattern or choose a color or something, I don't know.
I think this site should have an optional "Dark" Theme, Where it's the same green colors, But in Combination with Black, or Darker Colors that the User can choose to have the site be shown in instead. Like on Fur Affinity! ^.==.^