"I've never seen him or read anything about him that ever had him more than a guy who could touch 95 with the wind at his back."
A scouting report from the beginning of 2007 stated that he "occasionally touched 94 or 95, but that could eventually become his average fastball. You have to remember, in 2007 he was still a teenager, they likely figured he would get stronger and also improve velocity with improved mechanics. If he had gone to a 4 year college, this would only be his third year in professional baseball. If he has figured it out, then he's still ahead of most.
Tillman is younger than Arrieta, Ayala, Berken, Britton, Chen, Drake, Eveland, Gonzalez, Gregg, Hammel, Hunter, Johnson & Johnson (lol), Lindstom, Matusz, O'Day, Patton, Pomeranz, Strop, and Wada.
Tillman is not younger than Dylan Bundy, though. So he's the second youngest pitcher on the 40 man roster.