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.
I speak chaos.