I've watched a lot of both. When I watch them right now, this is what I see.
Wagner is a combo guard, can play both positions really well. He is more of a shifty in small spaces kind of guard (SGA, Maxey) not an elite speed and athleticism (John Wall) point guard. One of the things he does well like SGA is hesitations and change of pace. He will not physically overwhelm the competition but at times will make the hard plays look easy. I am not saying he will be SGA, but both just have a smoother style of play.
He also just has a knack for finding ways to put the ball in the basket. Wagner is not nearly as flashy as Dillingham but knows what he wants to do and can figure out a way to get to the spots he wants to.
Dillingham as far as Kentucky guards go I really don't have a comp for him because he plays so differently than most of the guards we have had. I think about him like two slight and wiry guards like a Lou Williams type (instant offense) if you want a more contemporary comparison would be Brandon Jennings. Very shifty, a lot of shots look off balance but are good anyway, can make defenders change direction (which is the goal)
Dillingham is very sudden (quick) and sometimes has his man beat after move one but wants to do moves two and three anyway. I think the coaches will help teach him how to get downhill after the fewest moves to beat his man rather than dancing too much with it (although there will be some of that).