If you had total authority over a city and found that you were no good at taxing, wouldn't you delegate the task to someone who was? I think the tax farmer ancillairy belongs on the bad taxer side.

On the larger issue, is there an agreed upon set of triggers for the farmer and trader traits that doesn't depend on the advisor? I've found her to be more like a trophy wife than an advisor: pretty to look at until she opens her mouth. The woman is utterly daft, and I don't want anything important like economic traits left in her clueless hands.