Speaking as someone with a slow computer: An option to pause the animations when your opponent plays a card until you acknowledge it would be really nice. I keep having it lag out until my next turn, and I don’t even know what card they played. This would also be nice to allow you to examine the card as it’s played. Obviously it would be disabled or have a short timer for games with other humans.
Unrelated: In multiplayer games, it would be nice to be able to examine your allies’ boards. Also, to have some sort of indication, when a card is played, who is playing it and who their target is.