9 cards is pretty excessive and just like with Seaside, the cuts also include cards that aren't turning the games into 9-card kingdoms 99.99% of the time. Not sure how I feel about this, but we will see when the 2nd editions actually release.
Anyway, my predictions from most likely to least likely. The first three are cards that we can miss easily without replacements that replicate those cards. For the rest, removing seems a pretty bold move.
1. Royal Seal: This is just a boring card that is extremely unreliable at being anything more than just a $5 costing Silver. While this was always weak, Way of the Seal and Bauble make this thing look incredibly stupid.
2. Trade Route: A very poor trasher, very poor source of +Buy, and Forager does whatever this card tries to achieve insurmountably better. It also doesn't help that this card is super wordy and requires additional tokens.
3. Contraband: This card has a penalty that makes this card borderline unusable in pretty much any board, unless your opponent is really missing your strategy. As a source of +Buy, it is also pretty much the worst as its penalty completely negates the ability to bypass the dreaded one-province-per-turn limit. (and generally, a $5 gold just isn't interesting these days)
4. Venture: This is a card that used to be regarded quite fondly, but just has no place anymore these days. It is completely useless with draw, and it is also pretty bad without Copper trashing. And even outsite of these cases, it is still rather unimpressive. And of course, comparing favorably to Adventurer no longer counts.
5. Loan: This card isn't too bad, but becomes pretty luck based as soon as a second Treasure that you don't wanna get rid of enters your deck. And what does this trasher bring on table that other trashers don't? It is also the card that Donald X originally considered as "the only dud of Prosperity".
6. Hoard: It is a fine card, albeit on the uninteresting side. The real kicker against this card is that it is almost exclusively useable in Province games; a really bad feat for a Prosperity card.
7. Counting House: It is part of the utterly obscene combo called Counting House + Travelling Fair, which some consider to be the strongest synergy within the entirety of Dominion. But does it ever get used outside of that scenario? Prior to Adventures, the answer is yes (but very sparsely), and it was satisfying to massacre unsuspecting players with this, but nowadays it really doesn't seem to be.
8. Goons: This card is a pretty frustrating to play against, as the handsize attack causes makes it difficult to come back when falling behind. Another thing to consider is that fact that Donald X wants to retcon the use of "While this is in play" out of existence. While the solution is trivial in most cases, Goons's in-play effect really shouldn't be Throneable.
9. Mountebank: I've never really had much problems with this card. But it is not very Prosperity-y and if there is another Curser in store for 2E, then this one should go. And yes, handing out 2 junk cards on a singular play is excessive, as is being able to junk even when the Curse pile is depleted.
