First off, neither one should be a lottery pick IMO, maybe at the very end.
That being said...
Do you take a guy who can't create his own shot, pretty much only shoots jump shots, and depends on others to set him up but is 6 '8.
Or, do you take a guy who can do everything but shoot jump shots, can get his own shot and is great at setting others up and has an almost unparalleled skill set for some one 6'8 270.
Its a hard question. They both have huge holes in their game IMO.
I would take Royce though, I think he has a higher ceiling. What he did when it was time to step up vs. what Barnes did is significant IMO and demonstrates not only more ability but more competitiveness. I also think it will be easier for Royce to develop a decent jump shot vs Barnes developing an nba style driving game when he cant even create his own shot in college.