I like Borough. It's very similar to another fan card I've played with a couple times (don't remember where it's from or who it's by), but Borough is more interesting.
I'm a bit worried it's too strong for $4, but if it is I could cost it at $5 and possibly give it another small bonus.
I like that Pickpocket gains directly from the trash, for the interaction with Trash-for-Benefit.
Well Barrister also gained directly from the trash for this same interaction. Really the point is that players shouldn't be able to foil Barrister/Pickpocket by trashing their Domains/Lucky Coins. The Trash-for-Benefit interaction is a nice side bonus and also the reason Domain/Lucky Coin cost $3 instead of $0.
Pickpocket is a Moat that can gain a single Gold over the course of the game in 2P games. It also gains a Copper, clears out an opponent's deck by a tiny bit and harms his hand for a single turn. I'm really not sure this is worth it, but it might be fine.
Pickpocket's bonus is +2 Cards rather than +$2 mostly to distinguish it from Cutpurse. You're right that it's pretty unattractive in the cases where it only works once (although in lots of Kingdoms you can trash your own Lucky Coins and then gain them back with Pickpocket). I could just use +$2 (which is at least better than +2 Cards) or I could try for a different bonus. It wants to be short, whatever it is; either vanilla or one line of text. +3 Actions seems interesting, but then you're just getting it for the Actions and the attack is incidental. It could be something like "Gain 2 Silvers" since if you're buying Pickpocket, you ostensibly want Treasures in your deck.
I still prefer Domain as a VP card... The think I don't like about this version of Doman/Lucky Coin is that has no special value for the player who started with the card in their deck.
I like Pickpocket's basic concept (I also like Barrister) but it will have the same issue as one of the early versions of Barrister in that it will often whiff in 2-player games. Now that might not be a problem because if it hits its both good for you (although you basically gain a Copper in addition to your Gold) and a Cutpurse-ish attack (which means it gets even worse in mid- and late-game. Because Pickpocket is so unreliable and Lucky Coin is a burden, I assume it is often best to trash your Lucky Coin and get stronger draw cards and more reliable attacks or cards that are better for your economy. That's why I like Domains better - you will often want to keep those. Maybe there's room on your set for both Domains and Lucky Coin.
I see what you're saying, but on most boards there's no good way to protect your Domains anyway. You can bloat your deck, and sometimes you can Herbalist it or what have you. But mostly it's luck. And it's no fun to steal Domains early on, carry them (basically Coppers) in your deck all game, and then lose them right before the game ends. I feel like Lucky Coin will mostly function the same (you want to steal them, just like you want to steal Domains), but will be less swingy and also be less annoying to players who hate having their VP stolen.
I doubt I'll have both Domains and Lucky Coins, though it's possible that I will go back to Domains.
I see you decided to let Wanderer go to the player on your left. Personally, i'm glad you did, though it doesn't change my general concerns with the card.
Yeah, I realized that in a 2-player game Wanderers that you play can get back to you pretty fast. I decided I didn't want it to play that differently with more players. It's still usually going to get back to you more slowly with more players, but not as slowly as it would if you passed it to the right.
I hope the concept works out; I think it's a neat idea. If it's not enticing enough, there are things I could change.
• It could cost less.
• It could have a stronger on-buy ability.
• It could have a stronger on-play ability (e.g. +5 Cards). This may seem like a wash, but being able to play the card first is a real bonus, and the stronger the on-play ability is, the stronger the ability to play it first is.