For that level of UTF-8 editing, a non-mulitbyte version of the editor suffices. In fact, you can insert and modify multibyte signatures and names using the map facility, however the glyphs are not rendered on screen but are shown at the byte-level.

Improvements are in order, and should be made, but the mere inability to visually render multibyte characters is not always a showstopper.

Do they right-align their command lines and files?

Or once the Arabic exceeds 50% the alignment of the buffer flips? :)