Projected splits of 90/99, control of 90 and velocity of 90.  But pitches of 85/52/60/37

Can he be dominant?

85/67 isn't that bad.  The other ratings should easily make up for it. 

sorry, i put it wrong. it's 85/52/60/37!

I have a guy with 73/73/67/40/40

and splits/control  lower than yours. And he won the Cy Young in his rookie year

I don't think that a pitcher can possibly have bad enough pitches to not be good with 90/99 splits and 90 control.

I'm with kc.
With 90/99 the guy is REAL GOOd with three pitches in the 60's!  Here's BruceDelluci.  Very similar (Control of 92, Velocity of 85) , but with 4 pitches between 64-70.  He's won two Cy's, and is 127-52 with a 2.48 ERA over his career. 

Your guy is that good.  He's a stud.  Can I have him?

Delluci was the 8th overall pick??  Holy s--t.

Before I entered the league.

The guy who went #1! Gilbert   100-101 for career.  1.40 WHIP, 4.71 ERA  Go figure

This guy went #4.  The only guy drafted ahead of him that might be even  considered as belonging there. Nobody else is even close.  Valdes  Career numbers at 1B  .300-.391-.591 w/402 HR's. He's only 29 with 200 HR's in last 4 seasons.  He'll end up close to 700 HR's.

Bradley went #6.  129-72, 1.24/3.43  Still not close.

I have a guy with lower splits (72/94), control (86), velocity (87), and does not have a single pitch over 69. He's won two CY youngs and has been pretty much dominant, most likely a future HOFer. I have my doubts your guy will reach those projections but if comes close he will be a perennial all star and possible HOFer.

You can get away with mediocre pitches, if the other ratings are good.  Yonder Trevino seems to have done well (in a hitter's park no less), despite his 76/59/71/39 pitches