Dominion, like many games, is quite thematic. For the most part, the names accurately reflect the function:
Villages gives +actions, implying that you need people to carry out orders
Conspirator makes sense, you need a lot of them to be useful.
Etc.
As pointed out before, Minion and Pawn aren't too good for names. It's hard to see how they line up with the function.
JoaT makes sense in that it does a little of everything, but as the recent DS article points out, chances are you go doublejack (or some other simplistic BM-type strategy) or skip it entirely. Maybe it should be called Master at One?
What nicknames would you give to the cards (perhaps some derisive ones for Familiar)?
Or, if you were given a whole set and decided to base it around a different theme, what would it be?
edit: Ah, what a coincidence, somebody recently posted a retheme.