If they were to make a deal including the return of their pick, it would be for the 2014 draft, and not the upcoming one, which is considered a weak draft by comparison. As for waiting, there's always the possibility that the Kings make sigificant deals in the offseason, and then make the playoff's next season. If that were to occur, or even if they were to just miss, the Cav's would automaticly get their pick, and in a far more talented draft. To put it in prespective, out of this group that will be in the 2014 draft, Andrew Wiggins, Jabbari Parker, Andrew Harrison, Julius Randle, Aaron Harrison, Aaron Gordon, James Young, and Noah Vonleh, all could be the first pick in the upcoming draft if elligible. Now obviously, there will be some failures in that group. There always is. But I think you can see why it might be a good idea to wait and see, rather than make a deal now, that maybe could be made next season.
From the Kings prespective, it might be advantagous to make such a deal this year. I just doubt that the Cav's would want to make such a deal. Besides, I think they can get much more than that for Varejao. And no, its not foolish to think its Cisco for Varejao, if the Kings were to make the playoffs's next season. They would have given away Varejao for a pick they would have gotten anyway the next season.