I'm a free-to-play customer right now, and the one thing I can think of that would actually make me buy Silver or Gold would be to add another option to the "AUTOMATCH" list for Game Type.
3) Classic or Speed
Classic Dominion = The game as it is now
Speed Dominion = Each player gets a 5 minute timer, and every moment that the screen banner reads "Your Turn!" the timer starts a countdown towards zero. Yes, this includes time when a non-active player is responding to an attack requiring a discard, or an Advisor/Envoy pick-a-card. Any time it's "your turn" and the game is waiting for you... even if disconnected due to an internet problem.
When a timer reaches zero, the player who exhausted their clock automatically resigns.
Justification: I often have only 10 of 15 minutes to kill. At times like this, I don't want to be stuck in a game with some perfectionist rank 50+ player who wants a 30 minute session so they can play every piece of their 40-card deck each turn
I respect that level of play, but I'm not always interested in being a part of it, and I don't want to be forced to resign just because the other player is trying to prep for a Tournament Game when I'm just here to kill time and have FUN.
DETAILS: Just like 2P and 3P have independent player ratings, Speed Dominion IS A DIFFERENT GAME than Classic Dominion. Players must have separate ratings for Speed vs Classic (identical to the current treatment of 2P vs 3P rankings).
Those who don't want to play Speed... just don't enable it, and stick to Classic mode. On a weekend when I have no schedule and no other tasks going on in my life, I'll enable Classic mode. 100% individual player choice.
Make it a paid feature so that one of the players must be Silver or Gold in order to start a Speed Game (just like the current logic for expansion decks).
If I see this feature, I'll get out my credit card!