I've been pondering this, and I'm curious to find out what potential issues could be created by even tightly licensed necromantic practices. Would the economy simply scale up to cover the extra workforce? Would this, essentially free, form of labour lead to a utopia of worklessness and free goods?
Edit for clarity: Yes, apologies, I intended the mindless dead. I've been pondering on the effects of raising Granddad for his weekly visit, but I think that touches on such a different issue that it deserves a separate question at some point. I've shuffle the non-economic issues away, to reappear as a purely social question on the same topic at a later time.
Double or triple edit, I forget: I've changed the question to make it clearer. I'll go for the economic here, and focus on the social elsewhere, including religious, political, cultural etc. I wonder how many questions I'm going to end up spinning this out to :D. I assume undead controlled with magic, so they essentially carry out the wishes of the necromancer, in the manner in which the task was requested. This doesn't prevent the undead from performing highly skilled tasks, but tends to limit it to tasks that could be performed by the necromancer, since their intention forms the action, and if they have no idea how to perform the action, the undead has no idea either.