I’m sorry you feel that way. The whole point of the changes was to make the editor look cleaner. It was a community effort that started with Brainstorming for modern UI [Anki 3.0] - #35 by kleinerpirat. Several discussions and polls followed. With the beta out for a few weeks, yours is the first negative comment about the new editor look.
I’m on Linux and don’t use add-ons - perhaps we got a different perspective because of that.
Here’s an old comparison between 2.1.54 and the new editor design:
If the first screenshot looks cleaner to you, I’m afraid we got a different definition of the word (or just very different tastes) 
Both of these add-ons will be integrated into Anki at some point. Theme support is on my roadmap for the next few weeks and setting a background image is trivial. As for add-on tests, I suggest to wait a bit, at least until Henrik is active again and his PRs are merged.
Generally speaking, I think the goal should be to reduce people’s dependency on add-ons over time - to a point where managers like the butler add-on aren’t needed anymore. Anki can already stand very well on its own and we should focus our efforts on making the software itself better instead of limiting ourselves with legacy add-on support.
But that’s just the two cents of some contributor.