Because we don't have Hayward "locked up." In just two more seasons he's going to opt out. He'll be an UFA. There is NO guarantee he returns (or doesn't demand too much). Also no guarantee Hood develops into a consistent 3PT shooter. He's struggled this season. And he's been injury prone. He could continue to have the plantar issue throughout his career.
Stauskas might not be the best trade option, but I'm leaning towards getting back something for Kanter now. Hayward, Favors and Gobert are going to be $20M players. Sign or match a 4yr deal for Enes and that contract overlaps the new deals for Hayward and Gobert for two years and a new deal for Favors by 1 season. Even with a higher cap/tax, that potentially puts Utah in the luxury tax for those two seasons. Millers might be willing to go one season, but not two. Yes, I know, we could keep him and trade him in a couple of years. But there are cheaper options to play behind Favors and Gobert (guys like Booker, our 2015 pick, etc.).
Plus, if we get back a player on a rookie deal, it opens up a good chunk of cap space (no QO for Enes). WE can go get another player like Booker. I'd strongly consider the Stauskas deal, just based on the fact this draft has a ton of bigs. Heck, I'd even consider Utah drafting WCS over someone like Prozingis or Turner. That means Favors can play PF full-time. Gobert/WCS and Favors/Booker. Damn!