My thoughts:
Border Village: We already know it. It's great if there are 5$-cards that you would buy either way (especially attack cards or other terminals) so you get a "normal" village for free. Beware: Don't forget to buy gold too.
Cache: Do I want to buy this with a 5/2 start. I think most of the time there will be better $5-cards in the supply. Great if you can trash the coppers immediately with watchtower or turn them into silver with Trader. Great in a Gardens deck too: 3 cards for $5 is great.
Cartographer: I think it's a great card which is kinda useful on all boards. If you have many curses or victory cards you can discard them. Also great in the beginning where the recently buyed cards get into your hand earlier. It also stacks well because another Cartographer draws one of the "prepared" cards. Maybe you only don't want to buy it if you have already a good running engine
Crossroads: One of my favourite cards. +3 Actions is already great even without the drawing effect. So buy one with $2 left is rarely bad. But on boards with at least one additional victory card a nearly must-buy and very over-powered. You can start going green after the first turns. Imagine the combo-potential with Harem, Nobles and Gardens of course. Yesterday had my first game with Crossroads and luckily there was Gardens and Workshop on the table. Great. Hoard is also great for going green earlier.
Develop: It's very board-dependant. But I think it can be very useful in mid-/end-game to develop one card into a victory card and the other in another useful card, mostly a treasure card. Developing a $7-card like Bank into Province and a Gold in end-game or developing a Moneylender into a Duchy and a Silver in mid-game. But I still have to test it.
Duchess: Doesn't seem very useful. A silver for $2 is great of course. You can buy one with a 5/2 start. But in the later game it's only useful if you have a good running engine with enough actions and at least +Buy. The obvious good case is when Duke is on board.
Embassy: Drawing 2 cards for $5 doesn't seem very good. But imagine you play it immediately at the start of your turn. So you can choose 6 cards out of 9 cards which is great. If there wasn't the silver gain for the other players it were a good buy for a 5/2 start. But gaining a silver isn't that good in mid-game in colony games so maybe that would be a good buy in such games.
Fool's Gold: As already pointed out, mostly it's no good card. You have to buy many of them, so it needs it's own strategy. It's great if there are good trashers in the supply, especially Chapel, but Steward too. And of course it's great if there a heavy cyclers on the board. So Embassy for example seem to be great with Fool's Gold. Or apprentice a card and play another card for +Buy to get 5 Fools' Gold => 2 Provinces (5 Golds won't work!).
Haggler: I will look forward to test this out. Buy a Platinum, gain a Border Village, gain another Haggler ... or something like that. That could easily end the game on emptying 3 piles. Great is also that Haggler itself gives $2. Haggler would be a good buy in a 5/2 start.
Highway: Not very new effect. It's effect can not be throned, but it's a cantrip, so you can multiples of them. I'm missing the +Buy of Bridge. It reminds me more of Quarry instead of Bridge. So $5 seems a little bit expensive. Great with engines with enough buys I think. Wharf+Highway or Salvager+Highway could be great.
Ill-Gotten Gains: I don't like it. It's the only curse-giver in the set and only a one shot. And $5 is definitely overpriced. So you need trash-for-benefit cards and then you have a feast-like card with a one-shot cursing attack. Or you buy a new one for every trashed one.
Inn: Yes, more shuffling
! First that came to my mind was: Scrying Pool. I think those two can combo very well. So with this card you want a action-heavy deck, because you get the +Actions. Peddler could also be great with enough extra buys. If you have too many terminal action cards, you can also discard 2 terminal action cards with Inn, then buy a Inn and shuffle them back.
Jack of all Trades: A little bit too complicated for my taste. It combines Bureacrat, Spy, drawing and trashing. I think one buy at the start is good, but I don't think it's a very good card.
Mandarin: A cheap gold. As already pointed out, combos well with Black Market.
Margrave: Maybe my favourite attack in this set. It seems very overpowered. It nearly a Council Room for the drawing ability and then nearly a Militia. So: Council Room and Mititia already was a great combo. Now we have it in one card! I think playing 2 Margraves is mostly better than Council Room+Militia. I'm looking forward to see it in action.
Noble Brigand: A mostly better Thief. It gives +1$, it attacks when you buy it, steals only Silver and Gold and gives Copper. So it's much better. Only in colony games it can't steal Platinum and of course other treasures but you can buy them yourself if you have already the treasures from your opponents
Nomad Camp: Instant Woodcutter, nothing special. I don't like that it adds luck to the start distribution.
Oasis: I don't get it yet. It's an expensive copper. It only removes a little bit of drawing luck. But I think for $3 I would rather buy a silver. Or can anybody tell me in which cases you would buy this?
Oracle: A better spy-variant. Instead of one card, it works with 2 cards and you look and discard before you draw: great. I'm only missing the +1 Action, but I think that would be overpowered for that price. I think that can bring up hard decisions for discarding. Should I let you discard your estate and gold or not?!
Scheme: Great, especially for that cost. It's a cantrip and it let you prepare your next turn. Play Scheme, play Witch, put Witch back on your deck. If you had no action cards in play, put itself back. I think this is nearly never bad.
Spice Merchant: Also a great card. Trash for Laboratory effect is great. It stacks not as well as Laboratory because you have to trash. And if you don't need the Laboratory effect you can also choose $2 and +Buy. So it's very flexible, I like it.
Stables: Looks also great. +3 Cards and +1 Action is very powerful. I think with that card you don't want to trash you coppers, so you can you use it multiple times. So in a Province game you buy 3 Stables and 3 Gold and you're ready to go green. Can anybody simulate that?
Trader: As already pointed out, a very interesting card that can be great in Gardens or Duke games. It can empty the silver pile very quickly. It's also great againt Curse-givers, especially Mountebank.
Farmland: Very interesting. But I don't know in what situations it would work. Maybe in end-game if you have 9$ and only one buy in a Province game. So you buy a Farmland with only $6 and trash the remaining Gold to a Province. Or in mid-game you buy with $6 a Farmland and trash your Moneylander and get a Gold. Any other ideas?
Silk Road: Another card for Gardens. Imagine Crossroads, Gardens and Silk Road on the board! But I think for $4 you need at least 12 victory cards to make it worth. I correct: Imagine a board with Crossroads, Nobles, Great Hall and Silk Road!
Tunnel: Wow! What an idea! I think early buys can be worth it. Of course it's board dependant. I didn't count the amount of cards that would enable the ability of Tunnel, but I think in nearly every game there is at least one card that would fit. One question: It doesn't say "discard from hand", so cards like Adventurer and Library would trigger the effect right? So Adventurer would combo great! Buy one card that trashes your copper, for example Moneylender. Buy a Province if possible, else buy an Adventurer if possible, else buy a Tunnel. Can anybody simulate that?
