I had the same concern about Falling Anvil (does Bludgeoning, Electricity, and Fire, all at range, plus a host of negative status effects and defenses). The message I seemed to be getting from people was "Don't worry about it." Then again Falling Anvil (of the classes in the actual ToB) is aimed at Sword Sages, so you might take that with a grain of salt. You might say that you have to give up TWO other disciplines to access it, but I don't really know.