You probably ought to read:
http://www.opengroup.org/onlinepubs/007904975/utilities/sh.html
which explains what a conformant shell is expected to do.

This is approximately the definition of ksh (except both the AT&T
and pdksh don't conform).  I don't know how well bash does - but
given some reports about the way scripts fail when /bin/sh is bash
it must be fairly broken.

Of course most of what you are talking about is 'emacs' mode
editing - which isn't covered by the standard.

The netbsd /bin/sh is also reasonbly comformant - except that
it doesn't do pathname expansion in the editor.
In particular implementing '=' (word expansions) is interesting
since there is an implication that command substitution (expanding
$(...)) should be done!

After all 'cut and paste' remove most of the need for these
expansions.

	David

-- 
David Laight: david@l8s.co.uk