(The sidebar text should have better contrast!)
This is a response to the new Light Theme where the sidebar is white. But this will also look amazing in Dark Mode.
I think the current Light Theme where server/channel list is dark is a very good solution. This is because the server/channel list aria is separated from the chat aria by the usage of colors. It makes for clean and good looking design. But the reason this illustration was made, is because I read that Discord was planning to make the server/channel list, white just like the channel aria. This dosen't just make Discord look colorless and boring, it also takes away the important visual separation between the server/channel list and chat aria. It ends up being cluttered and boring. If Discord want the server/channel list to be light and not dark, the best solution is going to be to make it transparent. It looks amazing and makes Discord feel more like a native app. translucency also breaks up the server/channel list aria from the chat feed in a very clean and elegant way. It would have a more native feel. This is also supported in the latest Electron version.