It's done. I chose the Pico theme after seeing and inspired by the Readability Bookmarklet earlier today.
The upgrade is easy, however, I need to vim the Markdown.pl a bit to get around to this "Wide character in subroutine entry" bug that block all publishing.
Took a little while to understand the relations between a "Website" and a "Blog". I think I like MTOS5 so far. The new admin UI looks sharp. Maybe it'll make me write more. I do hope so.