That would be a junky effect. Really not worth it. Unless you're a monk. And weakening would be a broken effect at low levels, but rather useless at high levels. Like corrosion and DR. Unless you REALLY stack it.
I'd love some more monster classes, personally. You can add a new Animated Armor class to VHoS and then move vamp to Namtar's Lair. Then you can add a Demonlord (or something along that line) to Demonic Library. Also, can the special edition class be a monster? They're much more interesting than normal classes.
We made an expansion and it is awesome. Really, you should check it out, especially if you're looking for some extra challenge.
Download over at ddmod.weebly.com!