As with any changes, some are liked, some aren't.
I was disappointed with some of the cards that were removed.
I generally like most of the new cards. Some create some interesting new interactions.
The one thing they did was make these 3 sets a bit more complicated. There are more things to think about, thus potentially slowing a game down. This is especially true when playing the table version where you don't get prompted like online. While this is may not be that big of an issue for the experienced player, for the new and inexperienced player, this makes a game slower and harder to learn.
When I try to get new players interested in the game, I start with the Base and Intrigue. Those are all simple and straight forward cards. The next set I introduced was Seaside, then Prosperity, then Hinterlands. They all introduced 1 or 2 new concepts that could be easily grasped. Seaside, duration cards that did 1 thing for another turn. Prosperity, treasures that did things, victory tokens, and platinum/colony. Hinterlands, on buy/on gain.
Now in each of these cards have been added that do multiple things and add complexity.
In Seaside: Monkey, Blockade, Sailor, Tidepools, Corsair, Pirate, and Sea Witch.
In Prosperity: Clerk, Investment, Tiara, Charlatan, and Crystal Ball.
In Hinterlands: Guard Dog, Trail, Weaver, Souk, Witch's Hut (wording is confusing).
These add concepts and options to mull that are not simple to the newbie. It's easy to miss the interactions when playing at the table. For example, forgetting that Sailor gets an extra card for each one they player prior gained. Blockade, missing that a player bought the blockaded card. Pirate, missing that a player bought a treasure so you can play it immediately. Sea Witch forgetting that 2 cards have to be discarded on the next turn. Trail forgetting that it can be played when gained, discarded or trashed. Weaver forgetting it can be played when discarded. Clerk, missing that each other player topdecks a card from their hand, or forgetting it doesn't cost an action to play it from your initial hand. Collection, forgetting you get points for buying action cards. Having to keep track of all that or having to figure out the best way to use a card (Tiara, Tidepool, Investment).
It means there is more I have to help keep track of and when you are playing a multiplayer game, it becomes difficult to catch everything as well as play your hand.
I know all these cards won't be in any given kingdom and yes, I realize I can omit complex cards from a game for newbies and even use the v1 cards. But my object is to bring them along slowly introducing new concepts. Now there are more complex interactions to introduce with these cards.