Hey Asper,
We played a game today that included Mill and Minister.
The feedback on Mill was: nice idea, but it's 'never' a good time to buy it. it's cheap, but it's obviously a very bad opening buy, right, because well, the diversity in your deck is pretty low. But later, when there is a high likelihood of Mill actually providing good valued cards (4 or 5), you probably have a bunch of good cards already, and are ready to start provincing or something. The fact that it's terminal doesn't really help either at that point. The person who bought the card wasn't dissatisfied with it, but it didn't really help all that much for their deck at that point either. Maybe if it's a peddler with that benefit or an on gain benefit ('now and when you play it *insert effect'), that would be pretty cool. But as it's now, it could use something extra. The effect is cool and awesome, but it needs something more.
Minister was fun. It didn't see much usage, but it served some purpose. Not sufficient to commenate extensively, but it was neither overpowered or underpowered.
Maybe it helps to add that it was a 4 player game, so less turns than usual, less building towards a deck.