Alexis Ajinca, Ante Tomic, or Omer Asik, in that order, is who the C's should look at for the pick. They should take a big they can keep in Europe for a year or two to develop. No one they add at #30 is going to help retain the title next season, so why not use the pick to build for the future?
Idk why you think that the #30 could not contribute in his rookie season.
Powe was a second year player picked at #49, for example. There`s a good chance Danny picks someone who can contribute right away.
Considering his Draft history, he will probably do a trade on Draft Night.
You have to look at who is available. There might be some guys who could contribute right away:
Wings: Walker, Lee, CDR... and then Jordan, Forbes, and Weaver are lesser prospects who could as well, although I am not as confident that any of them are NBA players (I think Jordan has the best chance)
Bigs: White, Dorsey, and Hendrix are the only guys I really see contributing much right away, but White and Hendrix duplicate Big Baby and Powe, and Dorsey I just think will be a bust
So unless Walker, Lee or CDR falls to the C's, or they fall in love with one of those other wings, everyone else is a project. Guys like Jawai, Hickson, Thompson, and even Hibbert will likely need a couple years of work (either on their bodies...Hibbert...or their games) before really contributing. So all things equal, it might make more sense to draft a talented international guy, who you could keep off the books (and from eating roster space) for another year or two, while they develop.