Signing Dedmon or Powell to be our 3rd big doesn't mean we're not "moving the needle." You move the needle by improving the team. And that comes in all shapes and sizes. It doesn't mean that every player you sign (or give the keys to) has to be significantly better than the one they replaced/jumped ahead of.
Two high profile players gettting the most offseason "Kings" attention from the media are Nikola Vucevic and Tobias Harris. Both are terrific talents, but here's why I don't think either one moves the needle for the Kings:
Vucevic is an All Star and a fine all-around player, although routinely criticized for his defense. But, with the exception of a single quarter, he was terrible in the postseason this year as the Raptors targeted him with smothering defense and he could not find a way through. Until he proves otherwise, he will be suspect as a nice player who can't handle postseason pressure. Is this who we want to give a max contract to? Also a concern is how well he will fit in with our playing style/pace?
Harris probably should have been an All Star this past year when he was having his best season. Then the Clippers traded him to the 76ers where he could help Embid, Simmons and Butler become serious playoff contenders; maybe even champions. But he didn't rise to the occasion in the postseason. He wasn't terrible, but he played below his average. Again I ask, is this who we want to give a max contract to?
Now, if we don't resign Willie, we'll need a Center. Vucevic can be that player. He's not a rim runner, but he's pretty solid (except for the postseason concerns). But Harris is a PF (who can also play SF sometimes). PF is the one position we don't need to improve on, with Bagley, Giles and Beli all perhaps best suited for the PF position. Sometimes a team just needs to add talent and worry about who plays where later. But I think we're beyond that. We have lots of talent, but we need to strengthen ourselves at certain positions, like Center, backup PG, and backup SF. A max contract for Harris seems counter to that (unless Bags and Giles can fill the gap at Center).