This is also a question I would like to ask.
Enlightened by the answers on this line, I think a good soil tech should know exactly where to start, how to proceed and where to stop, no more and no less. A accurate interface with consultants, owners, officers and other stakeholders is of paramount importance. This will require that a qualified tech have a sound knowledge of geotechnical engineering, current code and pratice, a certain period of experience, creativity and a high sense of responsibility.