My overall impression:
Aesthetics: The cover arts are an improvement, most notably for Dominion. Moat with the blue tint works better for the Reaction frame. And, having more women represented is much appreciated and makes the game feel more diverse. I feel the money and VP could have been improved instead of having the giant symbols blocking the art. These treasures are an improvement over the bland ones we originally had, but don't look as good as the Base Cards ones. With that said, I do use Base Cards, and a lot of new players get confused, so I think these newer treasures will make it easier for players to figure out the values and costs of treasures and VP. In the end, I'll probably end up using these new ones since I tend to introduce a lot of people to Dominion. Also, the larger fonts on cards, and bolding stuff is much appreciated.
As an Introduction to Dominion: I feel a lot of bad cards are gone, and we are getting definite improvements that will make the game better to introduce newer players to. However, I feel that not all problems are solved. I think one more +Buy in Base would help new players set up engines. Also, I feel the recommended first kingdom should have removed moat, since my experience showing new players that card first makes them want to have it in every kingdom with attacks.
I think I will try playing the 2nd edition alone with new players for a little while just to see how it works, and how I feel new players connect with the cards. But, I think overall, this will be better for people learning Dominion. The 2nd Edition does have a distinct disadvantage in that likely millions of copies of 1st edition Dominion have been sold and with all the deck builders out these days, Dominion is not as popular as it used to be. In other words, I feel this should have come out a few years earlier instead of now. But, hey, better late than never.
Also, I feel we still have some weak cards still left such as Bureaucrat and Mine. I guess new players like Treasures, so there's that going as a plus, but both of these cards are pretty weak. So, maybe Donald X. could have been more aggressive in updating the main Dominion game.
Removed Cards:
Chancellor: Almost always useless and rarely bought. You only got this if you had nothing better to buy on $3. Honestly, I'm not going to miss this card.
Thief: This card is weak, weak, weak. Arguably weaker than Scout. It also has the problem of scaring new players. I know most people new Dominion hate this card with a passion, so good riddance. Now, if only Possession could get a replacement.
Woodcutter: Okay, people bought this card, but only for the +Buy, not because they actually wanted it in their deck. As far as +Buy cards goes, Woodcutter is outright boring. I'm not going to miss it. Still, though, for the sake of new players, I feel Base Dominion should have added one more +Buy card.
Feast: Lame card is lame. I do admit, though, to sometimes opening Feast to get a power $5-card. But, honestly, who really likes Feast? I'm glad to see it go.
Adventurer: Potentially the weakest card in the game. Getting rid of this only makes Dominion better.
Spy: Yah, I rarely ever bought this. It just isn't worth it.
Scout: Do I need to say anything?
Coppersmith: I very rarely bought this card. I know some people are sad to see this go, but usually you just trash your coppers in an engine and rarely does this card ever shine. I think I actually buy Chancellor more than this card. Personally, I won't miss this card.
Great Hall: Doesn't really do anything. We're getting Mill. Now, when is the 2nd edition of Seaside coming out? I would be more than happy to see Pearl Diver go. And, yes, I know Donald X. said we aren't getting a 2nd edition of Seaside. Though, I can always dream.
Secret Chamber: This reaction is always a bitch to resolve. I mean, it was a nice card to use with Scrying Pool, but rarely was this card ever good. Out of all the cards, this is probably the most deserving to go just because of all the AP it creates and also how much it slows down the game. Trust me, some people I know can spend forever deciding how to resolve SC.
Tribute: I only ever buy this if I am desperate for a village. The card is wonky, and I'm not really going to miss it.
Saboteur: This card is weak, and to new players it seems like an awful nasty attack in an expansion that is already filled to the brim with nasty attacks. While Donald X. intended Intrigue to be about choices and alt. vp, we all know that's not really the case and Intrigue is really the evil attack expansion. Losing this card is an honest blessing.
Intrigue Base Cards: Saving people $5 is a smart move. If people really want more treasures they can buy the Base treasure cards.
NEW CARDS
Artisan: This replaces the $6 dollar slot that Adventurer took, and I guess it sort of resembles Feast. This is a lot like Altar, but instead you put the card directly into hand and then must put another card on top of your deck. Overall, this seems solid. We all now how good Altar is. While this doesn't trash, putting the card into your hand seems a reasonable trade-off. I think this will be a similar power level to Altar, but as far as cards for new players goes, this miles better than either Feast or Adventurer.
Harbinger: This reminds me a lot of Scheme. You get back a key card and get to use it again before your next shuffle. We know how good Scheme is. I expect this to be of a similar power level. This seems to be the Chancellor replacement. Again, this miles better for introducing new players.
Merchant: Hmm, so it can be a Peddler for $3. I think this is okay, but you either need a high silver-density or be drawing most of your deck. I think this is probably slightly better than Caravan Guard since you get the money right away. Although, like Caravan Guard, it does have a wonkiness to it.
Vassal: Okay, this card is weird. So, essentially, I play this which allows me to play another action and I get $2 extra on top. I don't really like that this is terminal. As for power level, I'm not sure, but this seems weak. I guess this is meant to replace Woodcutter and Chancellor as the terminal $2. Still though, I don't really know how often I will want to buy this card. Ehh, it's got to be better than Woodcutter or Chancellor, so there's that.
Poacher: This is pretty solid. In the beginning, piles likely won't run out soon. If you get 2 or 3 of these, you should be fine. Later on though, they kind of suck, first turning into an Oasis, and then an awful Oasis. Still, though, this card seems pretty decent to me. Not the strongest $4, but not the worst either. Maybe a mid-$4 or so.
Bandit: New players love Gold. I guess having a gold gainer like this is a good idea. This is vastly better than Thief. Still though, the card seems on the weaker side of $5's, but I think players learning Dominion will dig it, so yah. Still though, I think this is overall a weak card.
Sentry: This is strong. Being able to trash two cards is no joke. Sure, you can't trash from your hand which makes JD so strong, but early on Sentry seems very solid. I have a feeling this is an exceptionally good trasher. I do think newer players will get confused with both this and Chapel, but maybe by having another trash card in Base, they will get the idea that copper and estates are bad.
Lurker: This seems nice. I guess Donald X. realized Rogue really wasn't all that great. This allows pile control and can also help you get expensive cards quicker. Though, you have to be careful that your opponent doesn't swipe your stuff. The fact this is only non-terminal and $2 is really good. Still, though, seeing how the closest cards to this are Graverobber and Rogue, it's really hard to tell just how strong this card is until we actually start playing with it.
Diplomat: Good bye, SC. The Reaction is super good. And, the fact this can be a Lost City is awesome. This reaction seems solid. Though, in games without Attacks, I don't see it getting bought much, though, this seems a great candidate for Draw to X engines especially since this is a village on top.
Mill: This is a more interesting Great Hall. It kind of uses the effect from SC. It doesn't seem super strong, but it's decent, I guess. Actually I have no clue. Well, it's more interesting to have around than Great Hall, let's just say that.
Secret Passage: I understand that this is essentially a cantrip, but this seems really strong, you can potentially set up engines for future turns, and early on, you can tuck estates at the bottom of a shuffle. This seems to be a slightly stronger Fugitive. I mean Fugitive isn't great, but it's not bad either. I think Secret Passage will be slightly above mid-tier as far as $4's are concerned.
Courtier: Yuck, this looks weak. Okay, I agree this is better than Tribute, but usually at best, you are looking at 2 options, 3 if you're lucky to have a Duration-Attack. Regardless, none of the options are that exciting. I guess if you need +Buy, you buy this, but I really foresee this being considered one of the weakest $5's in Dominion. I'm surprised this actually made it to print seeing how this is about improving the expansions.
Patrol: Wow! Scout becomes good. Early on, this will be great terminal draw, especially when no trashing is around. Mid-game it's a $5-Smithy which is actually very weak, but then once you start greening, it picks up again. Oh, and it also draws curses. As far as terminal draw goes, I think this is just below Journeyman and Catacombs. Probably on a similar power level to Rabble. Though, I'm surprised, we are getting this in Intrigue. We already have Nobles and Torturer, like Attacks, Intrigue seems also heavy on draw.
Replace: A remodel variant is always welcome. The attack is weak, but seriously, did we need another attack in this set. Also, this is the third card in Intrigue that can dish out curses. Nonetheless, the whole curse giving thing comes into play later on. Earlier in the game, you are going to be using this to gain engine components. This is nowhere near Butcher territory power level, but this will be a decent card to have in most engines.