The actual word thaumaturge comes from a Greek root that literally means "works wonders" (thaumatourgos -- thauma(t) [wonder] + ergon [work]). In more modern definitions, it really can be as simple as "magician", as complex as "miracle-worker" or as common as "someone who does some pretty neat stuff".
It does not have a propensity toward offense or defense or healing or any other "type" of "wonder". If another game or story used it offensively, it would be completely interpretive of that particular
game or story. So reading too much into the actual word "thaumaturge" probably isn't going to work out too well. It is a very vague term in and of itself.. they probably knew it too when they assigned it :P
I'll bet you can learn any type of magic, but each magic type depends on your weapon, and your class depends on what skills you have equipped.
Based upon all released information by SE about your skill sets being dependent on your equipped weapon, and that there does not exist the previous "job" system we are long accustomed to from FFXI [instead bringing with it the class system, based on ability sets which are attached to the changing of a weapon].. I'd say this is a possibility of some kind, though in what capacity I'm not yet sure. Edited, Mar 8th 2010 11:24am by happybyday