Royce definately got a lot of attention for himself by his play today. However, scouts don't draft players based on their good games only. They'll look over all of his games and see that there is some inconsistency.
Now I don't pretend to know what's best for Royce... but my opinion (which isn't worth 2 cents) is that he'd benefit from coming back for a second year to show that consistency (both offense and defense). The numbers (points) improve a little bit. Keep the assists and rebounding up. Turnovers go down a little and you'll see a lotto pick.
Right now, I'd guess he's a second round pick, and I don't think any sophomore should settle for that when you can raise your stock as much as Royce still can. (He plays like he did tonight day in and day out next season and I see a top 3 pick next year)
If he were a Junior or a Senior, I'd mayby agree he should go pro. But he can do so much better in college with a full year of experience under his belt.