This was always an iffy thing for me. The staff is over 5 ft long, which makes wielding it in 1 hand problematic in reality. I understand that even PnP allow it, but I always found it to be a bit over-reaching. If you're going to do that, just make a club version, or have the staff shrink into a club at the wielder's command.
Check out Gandalf in LOTR and the Hobbit, wielding a longsword and staff at the same time. I know it’s not practical but it looks cool as hell, and D&D is supposed to be about these kinds of heroics.
