If Giannis spent the year before getting drafted playing on a top team in the Israeli league, as opposed to a 2nd tier Greek team, he might have gone top 5 in the 2013 draft.
Especially if he had already grown to 6'11'' (remember, on draft day he was only 6'9'').
As it was, Giannis was basically an 18 year old that got drafted out of a gym in Greece playing what amounts to high level pickup games, because of his physical measurements and some tantalizing grainy footage with image quality on par with some videos I've seen of Bill Russell from the late 60's.