Interactive /bin/sh

[dt71 at gmx.com]

Ian Lepore wrote, On 12/15/2013 17:34:
> An alternate viewpoint:  I would prefer that /bin/sh remain as lean and
> mean as possible, conforming to posix and especially NOT becoming
> bloated with interactive usability stuff.  If you want a user-friendly
> bourne shell and can afford the memory and cycle bloat, use bash.
>
> Please keep /bin/sh lightweight for embedded and dedicated-purpose
> systems that need a posix-conforming shell without a ton of overhead.

sh: Prefix-based history navigation is a must, but is missing.
csh: Is incompatible with sh when it comes to single-quoting arguments: WTF is up with '\!'?
bash: Is ultra-bloated, even with non-interactive extensions, which I don't need.

Is there a shell which differs from sh only by having more/better interactive features?
Or: why is there an interactive mode in sh?

BTW, I guess that the history thing is part of libeditline.