I'll disagree with the premise of this article - that he's a dynasty buy. I think he's more of a sell, if anything.
Wacha has a very high floor considering that he already has very good command and two very good pitches. However, he's going to stick with that curveball, which projects as no better than average. His two best pitches are indeed very good, but definitely not elite. His FB does have room to grow, especially considering the increase in velocity when he was stretched out as a reliever, but it doesn't have a ton of movement and I doubt he's able to stay in the mid-90s with it while a starter full-time. That being said, his "stuff" as a whole doesn't project him as having tremendous upside. Most scouting reports I've read have his ceiling as a #3 SP. Solid, but nothing spectacular.
Considering his showing in spring training and the hype that he's garnered (like ridiculous statements I've read where fantasy players would rather have Wacha over fellow prospects with considerably better stuff than him), I think his value is much higher than his potential should indicate. John Sickels has him ranked #34
, and I think it's wise to capitalize on that hype. When I'm gambling on young MiLB arms, I'd much rather bite on a player with ace upside, but maybe that's just me.