Thaumaturgy is only as useful as the objects used in it. For instance in artefact construction it's effective because the materials already have powerful magical properties. A line of something like brickdust has very little value so it cannot be used to create a powerful ward, but since an enemy won't (not can't) cross one unwittingly it can be useful to a cunning thaumaturge to determine if someone secretly bears them ill will.
Revising the subject of thamaturgy as a whole it needs to be up-powered and made far more interesting. One doesn't spend a king's ransom in an expensive chamber to perform pathetic tricks. A Master Degree ritual would be capable of preserving the dead in the world of the living (see mummies and wights from Warhammer) or other similar miraculous feats. Such rituals are powerful supernatural practices in their own right and a skilled and well-resourced thaumaurge is a dangerous opponent. Such rituals might be confused with low level effects of sorcery.
A note on thaumaturgy and it's relation to sorcery. Although Essence is the power behind sorcery, the use of expensive ingredients cannot be avoided in thaumaturgy. They are an essential part of the process and even Essence wielders cannot avoid their use. Essence use is for sorcery, and no matter how all powerful an Exalted may be, if they want to use the unique advantages of thaumaturgy, they have to abide by it's rules. Of course for them, acquiring such supplies is often considerably easier.
