I came up with the idea for my Alchemy "2nd edition" idea (which had a lot of events costing $P) as "rack", but I thought it would be worth revisiting with the advent of Coffers and Villagers.
Docks - "At the start of your turn, put all cards on this mat in your hand"
Terminology:
+1 Dock - Take the top card of your deck and put it face down on your Docks mat
Dock a specific card - Put that card face down on your Docks mat
So for example
"Caravan"
Action - $4
+1 Card
+1 Action
+1 Dock
Would have a similar effect - a cantrip that makes your next hand bigger. By not being a duration it won't miss reshuffles (and can be Princed), but with the new mechanic there's the risk of not having any cards to Dock.
Whereas
"Haven"
Action - $2
+1 Card
+1 Action
Dock a card from your hand
Is pretty much the same (except stronger for not missing reshuffles).
"Summon" (buffed)
Event - $5
+1 Villager
Gain and Dock a card costing up to $4
"Den of Sin"
Treasure - $5
When you gain or play this, +2 Docks
Simlarly:
* Expedition and Save are easier to track and not vulnerable to Militias
* Faithful Hound could dock itself. Horse Traders could dock itself and +1 Dock
* The River's gift could simply be +1 dock.
* Gear would be similar to Haven. It may be buffed enough to justify a cost increase to $4 (which IMO it should have been anyway)
* Similar to Den of Sin, Ghost Town (replacing the Action with a Villager). Cobbler would really miss being able to see your next hand, and by the time you've added a Navigator effect it's probably easier to leave it as a Duration.
* Tactician would really miss the next turn +buy, but Wharf wouldn't
* Not ideal for all situations. Enchantress, Haunted Woods and Dungeon need to be durations for other effects so no point turning their next turn +Cards into Docks.
Things the new mechanic could enable:
* "Expedition" type events would be far easier to do and keep track of
* Drawing extra cards next turn could be tied to things like when gain/trash/overpay
* It would be far easier to tie next turn +cards/"haven" effects to conditions (eg trash/discard for benefit)