I think it's unsurprising that Coppersmith shines in engines that can make big hands "the hard way" (by drawing - i.e., "disappearing village - draw to X" and Scrying Pool engines are no good), play multiple Coppersmiths and have the +Buy to take advantage of them. The fun part is getting the ratios right. You need a lot of +Card, and just enough +Action to play your Coppersmiths and +Buy to leverage what you've got. Any surplus is wasted, since the plan is to draw huge portions (if not all) of your deck reliably, so that "insurance" is not needed, and it comes at opportunity cost of more draw cards and/or Coppersmiths. And you want the Villages to be cheap, because you're going to pick most of them up early at Silver opportunity cost, and you really want it to be only Silver opportunity cost and not draw-card opportunity cost. And hey, picking up a couple later with spare +Buy can't hurt, so why not maximize the chance that you can afford to do so
Tactician is one of Coppersmith's best friends for all these reasons - 5 cards, 1 action and 1 buy is a pretty nice ratio, and you put it all together at once. I'm wary about buying a second Tactician here unless your deck gets really massive because you're not going to be building a double-Tac engine (unless you also have Black Market?). Wharf and Council Room are also great for similar reasons. On the Village side, Crossroads is, the first time, two +Action for a $2 card, and it helps you cope with greening too. So that's a great pairing as well. I'm skeptical that you really want as many as 4 of them in this engine, but it can hardly hurt if there's nothing better to buy, I guess.
Another example of Coppersmith, this time with Native Village and Wharf:
http://dominion.isotropic.org/gamelog/201212/29/game-20121229-094412-f4813732.htmlI didn't even buy extra Copper here, although I'm pretty certain that I should