Ingix - it's because it *feels* rude to deny undos manually - and often provokes players to be abusive in response, no matter how much we hold the principle that undos are optional. Undos on/off as a matching criteria would avoid this social difficulty - as it established the attitude towards undos before a player commits to game.
I intend to build this feature, but I am also afraid you will be very disappointed by the results.
I have a feeling that selecting "I only want to be matched with people that never allow undos" will turn out to be annoyingly close to "I like to just sit & wait here while not getting matched". The people that at least want to allow some undo's are an overwhelming majority.
I agree wholeheartedly. To date, I have played over 3,151 games of Dominion on this site. In all those games, I feel confident stating that I have only had a problem with someone denying a reasonable undo request a handful of times. Perhaps due, in part, to my low rate of undo requests, but moreover that the vast majority of players grant reasonable undo requests.
We've all experienced players who try to abuse the undo button, and those rare situations are, IMHO, what the deny button is for (and the blacklist).
Thanks for the game and your continuting efforts to make improvements. The latest one I noticed was the feature making it easier to see what you are topdecking with Harbinger - well done!