+1 to Polk5440.
For starters, every set needs some basic utility cards. Wacky, crazy Dark Ages still has Junk Dealer and Hunting Grounds and Wandering Minstrel.
Secondly, it's a great observation that new mechanics aren't the same thing as new strategies. A new mechanic can open new strategic opportunities, true, but not necessarily; and it doesn't take a new mechanic to introduce a new strategy. I wouldn't say Production Village or Tea House (just to pick two random examples) are new mechanics, but they certainly offer new strategic opportunities I'm excited to explore.
Third, although I can absolutely understand and respect the desire and hope to invent new mechanics (on a par with Potions introduced by Alchemy and Ruins introduced by Dark Ages and Platinum/Colony introduced by Prosperity) and would have liked to have seen some of that myself, I think it's an unrealistic expectation that that would occur in a set constructed card by card. Were we to create a fan expansion along those lines, I think we'd have to have a separate contest for choosing a mechanic and only then designing cards to exploit it. It's actually somewhat fortunate that we stumbled upon a theme of sorts -- a Copper theme, with Almoner giving cards like Pawn Shop and Aqua Vitae a wider range of strategic opportunity than otherwise.
That said, we do have some cards with new mechanics: Soothsayer, Pawn Shop, Canal, Harbinger, Missionary, Astrolabe, and Barge all seem like brand new mechanics to me, and a few like Crystal Ball and Gatherer straddle the line. That isn't so many that the set couldn't accommodate a few more, but too many such cards is arguably worse than too few.