[plt-scheme] v4 top-level based languages in DrScheme

I'm considering dropping the mzscheme and mred top-level based
languages from DrScheme. After some thought, it isn't very clear what
use they will serve beyond Pretty Big and R5RS, especially now that
module programs are so easy to write, via #lang.

Is there anyone out there that still uses mzscheme and/or mred in v4
or imagines that they would?

Thanks,
Robby