Whoa now. Nomo has had a stellar career. A fine addition to any fantasy team. I really think thats a terrible comparison.
Willis is hyped a bit right now - coming off a wonderful rookie campaign and World Series appearance. The chance that he will have upside value where he is being drafted is debateable. The jury is still out as to whether he will have a good career in baseball, or if he was a one yr wonder. Im not gonna make that guess. Im shooting from the hip here, but Im assuming there have been many rookie SPs who performed as well as Dontrell, but never made a long term career for themselves for one reason or another (injury due to mechanics, lack of maturity, telegraphing pitches, etc...). He will be much more valuable if he can put another season together like last yr. Given the revamping of the Marlins, Im afraid it isnt going to happen. He will see less run support, and will have a different C calling the shots.
The point is, he could be the next Oswalt, or the next Ankiel. Where I assume he will go in most drafts will be a best case scenario - meaning whoever drafts him will more than likely be paying full price for his 2003 numbers, and I dont see the value in that.