As a card, I think Governor's power curve is a bit steep, but I really like it as a piece of design. The point of the card was to feel like a game of Puerto Rico, and in that sense I think it does an excellent job of capturing the key aspect of gameplay, while doing so in a very Dominion-y way.
I hate hate hate Black Market, both from a card and design perspective. From a card perspective, it's too damn swingy depending on which cards you get dealt out. From a design perspective... the most important effect of the card (playing treasures during the action phase) is something that's not explicitly acknowledged in the card text! It feels like the awkward first draft of a decent idea, that got released before the edge cases were exposed and the exact mechanics were buttoned down into something that didn't necessitate breaking the game in ways unrelated to its intended functionality.
Compare BM against, say, Possession, another card that has a FAQ section the size of War and Peace. Possession messes with an absolutely fundamental aspect of the game, but it implemented the mechanics in an elegant and tidy fashion, where all the relevant effects are explicit and fit into the card text. The repercussions are significant, but they're all obvious in hindsight as direct applications of what the card says. BM on the other hand, breaks the game once by design, and then breaks the game again even moreso by accident, and the second way is not immediately obvious from the first.