MORE PROS:
1) I'm amazed by people who are so quick to lose faith in Danny. He's proven himself at nearly every step, even while many fans have second-guessed his moves or booed his draft picks. Almost every time, he was right and those critics were wrong, so why is this time any different?
2) If someone told you that they'd give you their 40 Powerball tickets in exchange for your 30 Powerball tickets, you'd be crazy to say no. The draft is definitely a gamble; no matter how many people talk about Fultz as a sure thing, history shows that they're wrong. Here's a 538 article that quantifies draft pick value using data since 1985:
https://fivethirtyeight.com/features/how-much-is-winning-the-nba-draft-lottery-really-worth/. According to their data, we win this trade as long as we don't end up with a Kings pick that's #22 or lower.
3) Let's say that Fultz has a 50% chance of being elite, and let's say that Jackson only has a 30% chance of being elite. Let's also say that the Lakers/Kings pick has a 30% chance of being elite. With just a little bit of simple math, you can show that this trade slightly increases the odds of getting at least one elite player.
4) The Cavs and Warriors superteams are tough to beat right now, so a more patient approach feels reasonable. Fultz wasn't going to turn us into a real contender. Even the combo of Fultz and Hayward wasn't likely to be enough.
MORE CONS:
1) If the goal is to trade assets for a proven star, this trade might be a step in the wrong direction. Both fans and NBA GMs seem to unreasonably overvalue the #1 pick. We may have just turned our biggest trade chip into less desirable trade chips that make it harder to land a guy like Davis.
2) If the next step is to trade for a guy like Butler or George, we might regret this trade badly. Adding Butler or George probably isn't enough to get us past GSW, so we could be mortgaging the future for a chance to lose in the finals a couple of times.