How difficult would it be to make the Discourse UI more like Flarum?

I wish there were more discussion here about some of the other potentially nice aspects of Flarum. Flarum just graduated to 1.0, finally. And although I continue to feel Discourse is superior in most respects, I also like some things about the Flarum design/UI. So I hope if others likewise miss some Flarum-like aesthetics, they will also chime-in here and maybe we can finally get a theme built (I, sadly, lack the skills, but may be able to contribute monetarily to a group effort on it if there is interest).

For now, to get started on addressing things besides the header, I believe the sidebar can be mostly replicated with:

Although it does not support Tags. Alternatively this:

Problem is that both appear to be in need of some update/maintenance or refactor.

One feature/design approach that seems entirely missing from Discourse, AFAIK, is a more obvious text box-like “reply” area, which I think is a nice alternative to the “Reply” button:

Notice how this is more than just a possibly “easier” or more “frictionless”-looking reply approach. The addition of the avatar image already there is actually an interesting detail that I personally think encourages interaction because it subtly makes you feel like you’re already involved.

In fact, I think this is probably a good enough idea to deserve a feature request of its own…