I've actually just revised the mutt-wizard in another important respect; this isn't much on the backend, but actually makes it a lot easier to use and install.
Instead of being a script you just have to keep in your mutt folder along with companion files, you can now just clone the repo and permanently
sudo make install it.
Instead of being an interactive loop, it's now a command you run like this:
mw init once to initialize the files, then
mw add to add an email account, etc. etc. That official mutt-wizard script,
mw, is installed in your path now, along with
mailsync allowing you to easily run them wherever and treat them like noraml programs.
Also, the template muttrc, mailcap and the domains.csv are held in
/usr/share/mutt-wizard so you don't have to worry about them cluttering your personal mutt folder proper.
Not quite sure why I didn't do this before, but now it should be even easier.