Saboteur is the biggest mistake here. Some people hate it because it can trash Provinces...
My thought here is to put the 3-6 range limiter on it, but make the card gain mandatory. Fixes the Province-trashing problem, but buffs it by making it a hybrid trasher/junker.
I would look at ways to buff Scout.
Letting it grab curses (and possibly ruins) would be a good buff, and I also like the idea I saw on another thread of making it a 0-pt Victory card.
Masquerade has a clear simple wording and I would rather kill the card than make the wording awful.
I wish that Lighthouse/Moat would let a player ignore the card passing, but that might be hard to do with a simple wording.
Sea Hag should be a more powerful card for $5.
+1 Card, Discard a card? That kind of goes in theme with Young Witch.
Lookout is the dud of the set. The problem is, some people are terrified of trashing a good card with it.
"In any order, trash a revealed card, put a revealed on top of your deck, and discard all revealed cards."
I do not look at Possession and think, oh I shouldn't have made that one.
I'm in the "no multiple turns" camp. One friend of mine who hadn't been playing very long got turned off of the game when someone used KC-KC-Possession x3 on her. It's just not fun for the possessed person to sit there taking orders for a half-hour. Or for the other players watching.
That said, Loan is easily the dud for me...this flipping over of cards thing has to come paired with something like "and get the good ones" in order to not bum people out too much.
It could do the Lookout thing and let them top-deck, discard, or trash their next Treasure.
Talisman would be a lot more exciting if it could get VP cards somehow, but some people do like it as is. There might have been a good tweak there, dunno.
Use the Horn of Plenty technique, and make Talisman trash itself if it gains VP?
Harvest does the flip over cards thing, and I would try to fix that up, see if I could make a version that did not make your good cards go by.
Flip over four, discard any duplicates, gain coin equal to the number of remaining cards, and then top-deck them?