I'm with Nathan and Sloth on this one. The response already happened when Saruman entered play, so Saruman dying or having his text box blanked would not retroactively invalidate the response.
It's like if you use Arwen's response to give someone sentinel and then she dies during questing. The sentinel still remains until the end of the round.
With the Wingfoot example, I believe you would still ready the hero.
Saruman dying should definitely invalidate the response because he is no longer in play.
What happens if Saruman dies and then you reshuffle your discard pile into your deck, draw him, and Sneak Attack him? Does that enemy that you previously chose go away AND you get to choose another one? If the effect is only tied to Saruman existing, then every time he exists the card you chose would have to be considered out of play. Due to this, his effect must be tied to his card text being active after you trigger his response. The second his card text becomes inactive (for whatever reason) his effect would cease to be present.
Arwen is different. It says "Until the end of the round" which has been ruled in the most recent FAQ to mean that it is a bonus that happens at the time of activation and any game state changes don't effect it.
Saruman and Wingfoot both don't say "until the end of X", although I can see the argument now and think that it is fine.
Since Saruman doesn't say "Until the end of the X" that means any time Saruman enters play the overarching effect that you activated however many turns ago is still active because technically, nothing has formally ended it??? That makes zero sense to me. It must be tied to his card text.
Edited by cmabr002