Much like pre-moves work in Live chess. I would like to see this as well.
Another conditional moves feature that would be good is the recognition and collapsing of multiple lines that transpose to a common position back into a single conditional line from that point forward.
There should be an option to allow the player to make conditional moves regardless of the opponent's move. This is particularly useful in some endgames, where, no matter what move the opponent makes, all you need to do is keep pushing a pawn. This can be accomplished with the current functionality, but requires the user to input conditional moves for a large number of possible variations.