And, perhaps most importantly, it could give you all the possible trashing combinations for when you play Forge! No longer will you have to add up every possible combination of cards from your hand, and then check the board to see what you get. Think of how much time will be saved!
You don't want a list with the 2^(#cards in hand) possibility what to trash, each entry dublicated for (#how many cards you can gain for that price) times. What you perhaps could do is hover over a "target" and get a list of cards that could be forged to this target, excluding dublicates, likely excluding 0-cost cards. Which you must add by hand.
Also +1 for no autoplay on Village. There are so many situations where you don't want it, to add some to the list:
KC,TR
Trash for benefit
reshuffle
good cards left in your deck, but already enough value in the hand
Menangerie/HP
Bad cards on your deck (Spy et al) and Native Village/Lookout
Pearl Diver/Apothecary/Scout usually wants to be played before the first Village the first time, for the second one it depends on what you see
empty deck + Vault/SC
I think you're looking at this the wrong way. Several of those situations are thoughtful, interesting decisions, yes. Added together maybe they even add up to a tenth of the times you draw a village. Maybe I'm off, maybe it's even 20%. But if the decision of whether to play a Village or not is removed, the time you would have spent deciding whether to play Villages vanishes. You throw out the baby and the bathwater and you chunk out 100 decisions per hour, 20 of which were interesting. That leftover time gets used somehow, and it's not going to get used for a slow animation where you watch the computer play your villages for you. (they wouldn't even really be cards probably, instead they'd be randomly occuring +action "events" or +actions you've enchanted your coppers with or something I can't think of)
Instead of that time you would have been quickly making sure "yes, I ought to play the village", you'll be choosing between Remakes and Tournaments, Markets and Outposts, Silvers and Chancellors. Those decisions are interesting at least half the time. So overall you spend more of your time doing more interesting things.
I guess it would decrease the overall breadth of all possibilities, but Dominion already has enough that it'd take a lifetime to see it all so I don't think that's an issue..