Were I to push a change to Casper, my sense is it would be rejected, as John O'Nolan (the Ghost maintainer) responded to the tweet I linked with:
> "It’s really not an anti-pattern. And it can be disabled with literally 1 line of code"
Since we disagree about whether these bars are good or bad UX, I believe that'd be a non-starter. And although it can be disabled, it adds unnecessary friction -- defaults should encapsulate best practices. As Ghost is a blogging engine that should appeal strongly to less technical users (by being simpler and better UX than wordpress), having to manually download, edit, and reupload a theme seems to not be in alignment with one of the key value propositions of the product. I doubt most users even change the default theme, and that's okay - frankly, that's a sign that the product is really good.
Since you're new here (or at least your account is new), HN is a community where we regularly discuss things like the scourge of downloading 5MBs of javascript in order to view a single news article, the importance of sane defaults, or other specific issues related to design and tech. It seems pedantic but its a place where people care about such things, and we don't typically tell people they're crybabies when bringing them up.
You basically have two option now: https://github.com/TryGhost/Casper/commits/master
Have fun :-p