It's not Marcus Smart.
If you want to see a guy who really got a raw deal when he went back to school, look at Oregon senior Mike Moser, who saw his college career end in their second-round loss to Wisconsin. Two years ago, after averaging 14 points and 10 boards as a sophomore at UNLV, Moser was seen as a sure first-rounder. Instead, he decided to return to school.
Last season, he broke his elbow and by the time he got back, he was firmly behind Anthony Bennett. Instead of being the star, Moser became a 6th man. Moser and Bennett never really clicked - his statistics were down across the board and he decided to transfer. That's how he ended up at Oregon - he was given an extra year of eligibility because he graduated in 4 years.
After dismal numbers last season, Moser regained most of his production from his breakout season in 2012, putting up 13 points and 7 rebounds a game on 46% shooting. Two years later, though, after not progressing much between his age 21 and 23 seasons, Moser is no longer on the top of everyone's lists. He's not even in the Top 100 for DraftExpress - he will have an uphill battle even to be drafted.
Moser is still the same player, just the perception of him has changed dramatically in the last two years. He may or may not be able to stick in the NBA - as a 6'8 230, he's a little undersized to play his college position (PF) and his time with Bennett proved that he's not nearly as effective as a SF. On the plus side, he's still pretty athletic, he's a good shooter and he has a good amount of ball skills - Moser can put the ball on he floor, start the break himself and he's a solid passer. In the right system, he could be a good backup PF in the NBA.
That is the issue - no one really cares about backup power forwards in the NBA. The D-League is filled with guys who could be backup 4's. There are 7-8 PF's in every draft. You miss on one guy, there's always next year.
People have this idea that the NBA is the Top 450 players in the world when it's really 150 of the Top 200 and 250 of the next 1,000. Talent is distributed like a pyramid. Tennis players are ranked into the 1,000's, but no one cares after the Top 100.
For a guy like Moser, who needs to be in a very specific role at the next level, there is no guarantee that he gets an opportunity. The higher you are drafted, the more slack teams will give you, especially if your first team lets you go. You have a pedigree - if a guy was drafted in the first round, he must have some talent. An undrafted guy always has to prove others wrong, instead of proving them right.
For a guy like Smart, it's all the same. Everyone in the NBA knows who he is and everyone knows he is talented - if he wanted to enjoy an extra year of college, it wouldn't be the end of the world. What would have happened if he had been drafted No. 2 by Orlando? While he probably could have put up numbers as weak as Oladipo's, he doesn't need people thinking he's going to save their franchise.
When you are talking about deciding for the draft, the decisions that matter aren't the ones made by the lottery picks. It's the guys projected to go at the end of the first round - they are the ones who have to plan it just right.