Painter has the big arm/big body combination of an inning eater.
He's high velocity without high effort, similar to Wheeler.
The reason teams like these guys if they have good mechanics, they can use their legs and body, taking stress off their arms, and maintain velo through 100+ pitches.
Of course, Painter has to prove out, but he's still filling out that frame. Probably end up 6'7 230+ when he grows up.
It'll probably take a couple more years, but the reason he's a top prospect isn't just the stuff, but the potential to be a 32 start, 200+ IP guy season after season.
Which is what makes Wheeler special.