Utley had a picture perfect swing, and he generally didn't chase pitches out of the K zone or overswing.
Franco actually has a short swing when he relaxes and just tries to hit the ball instead of mash it, same with Galvis.
Problem is they lose that discipline, start overswinging and chasing bad pitches and dig themselves into deep holes.
The guy who's really improved as a hitter is Hernandez, he's still not a great breaking ball hitter, but he's learned to lay off the low breaking ball for the most part, forcing pitchers to throw him FBs, bring up their breaking ball, or walk him. And you don't see him overswinging (though let's see if his recent HR orgy tempts him!).
When I look at Joseph and Rupp, I see great potential if they improve their discipline, they both have plus plus power, and they're willing to drive the ball the other way, using the whole ballpark. Joseph has the quicker swing, but I think their upside again depends on laying off bad pitches, running good counts and looking for balls they can drive. You don't have to be extreme to gain a sizeable edge, in 100 PA, if you can just be patient enough to get 10 more good pitches to drive, you can end up with 3-4 XBHs, over a season that's 10 extra doubles and 10 extra HRs. That's why patience is key for a good hitter, you just want to work to get a little edge in every PA, and over a season that can add up to big numbers.