The current version is capable of a few more editing features than the original, but it's still far from completed (hence the 0.40 version number). Planned in the future is BEX support and support for the Heretic/Hexen (Strife?) spin-offs. Special source port specific features (ZDoom anyone?) are also things I have in mind for 1.0. In short: Get rid of the original WhackEd if you used that at all and install WhackEd2 instead.
So yeah, go grab it.