Primogeniture and Dead Hand are like Inheritance for Duchies and Curses, respectively, except that most of the time these cards will still clutter your deck. It's not clear to me that you would want to gain Duchies or Curses in order to take advantage of Primogeniture and Dead Hand, unless you are playing with Archives and can stash them away for turns where they would not be activated. Setting it up through Succession also comes with an opportunity cost since you are removing an Action card from your deck. I could definitely see it being detrimental, since it will not only slow down your tempo but having Curses and Duchies in your deck during turns where Dead Hand or Primogeniture are not available will make your deck less reliable. I suspect that Estate Tax would probably be the strongest Law of the bunch and the most contested one.
I definitely agree with this analysis, and I think it is a potentially interesting design space for these. Effects that would be too strong as outright Projects or Project-like Events (like the ones in Adventures that use player-specific tokens) can be made into laws, where players will only have the effect some of the time--as I mentioned in my post, at most on 1/2 their turns. Depending on the number of players and if a Law is contested, a player might only be able to get it 1/3 of the time. Also, even if a player decides not to pursue the strategy (in this case, deciding not to set aside any laws), they can still use their token to limit their opponent(s) and limit their access to the most advantageous laws, without any opportunity cost (unlike something like Flagbearer / the Flag).
That being said, it is tricky to design something that is strong enough to make pursuing it worthwhile in those circumstances without making it too powerful on those turns that you do get the desired Law. The need for collision helps (here with Curse, Duchy, or a copy of the set aside card). You can choose to the cards in your hand at the start of the turn, but only if you aren't blocked or already there.
I did have one thought about some of the syntax. I followed Timinou's example from Industrial/Commercial/Economic/Sacred and used "At the start of your turn, . . . " (which is how an equivalent Project would be worded). However, a player's token is moved at the start of the turn. According to the official rules, when multiple things happen at the start of your turn, you choose the order in which they happen. Thus, a player who previously had their token on Economic could, at the start of their turn: (1) take the +$1 from Economic; (2) under the rules move their token to Commercial; (3) take the +1 Buy from Commercial. I am almost certain this wasn't the intention, and it could in theory be fixed by saying that a player's token is moved at the
beginning of the start of their turn. However, since the token is moved at the start of the turn, and that is when those bonuses are to be given, it could be simplified even further by being phrased like an Action card. Thus, Timinou's first example would become:
Industrial - Law
+1 Action
Commercial - Law
+1 Buy
Economic - Law
+$1
Sacred - Law
Trash a card from your hand.
Given that the Law only applies on that player's turn, even the more general Laws could be phrased more like Actions / Events, with the effect happening when you moved your token onto it. Thus, one of my submissions would be:
Primogeniture - Law*
This turn, Duchies are also Actions with "Play one of your set aside cards, leaving it there."
This could make the language cleaner and remove the need for the specific "at the beginning of the start of your turn" rule.
I did come up with one other set of Laws. This was actually the first idea I came up with, and while I realize it has a lot of problems, it got kind of stuck in my head. I do potentially like the idea of a negative/restrictive set of Laws, but this is probably not it.
Three Wise Monkeys - Law
At the start of your turn, reveal the top card of your deck. Move the Evil token to its pile (cards from that pile are Evil cards).
See No Evil - Law*
On your turn, you may not gain Evil cards.
Hear No Evil - Law*
At the start of your turn, discard an Evil card (or reveal a hand without one).
Speak No Evil - Law*
On your turn, you may not play Evil cards.