Official dark theme, seems to be made to look good. As someone who have designed my own theme and while doing so, the official theme problems seemed to come from design patten and workarounds from all cases, which i also faced: event size and order, different events after another, editor size, select focus hover style, reasonable contrast between everything, all which editor has to support and still look good.
To overcome thous problems, editor has to look very simple and with simple style. Or you just add a lot of padding everywhere.
And i think if official theme gets pure dark version, it won't look good. Black and white suits, but other colors get really messy, with no good contrast etc
It can look fine. Style it with colors similar to the dark theme, but keep all the other styling like grids, padding, etc... the same. Kind of like this below. I just edited the CSS in the browser.