A possible problem with just the drop on die would be the billet being a tad "sticky" sometimes, more so with squaring dies and might lift die off bolts. UNDERSTAND!!! I do not have the experience to even comment on that, but that was one of the things I considered before making this quick change setup.
The Coal Iron press has replaceable threaded inserts in the press, so it's not a real concern about buggering up the threads. Just screw the inserts out (if not stuck
and install new inserts.
Here are the widening/flat dies I just finished in the press. The welds are just tacked in at this point so they're really ugly! Not had a chance to use them yet, just finished now at 5:30pm.