If there is anybody that needed a couple of years of college, it's Gerald Green. He would have come into the NBA more mentally ready and would have had the opportunity to succeed early on, rather than hitting rock bottom and working his way back up. You're right, he is only 27 and there is no reason why he can't be a successful rotation player for the next 6-7 years.
I get the controversy with making NBA ready players go to college for a year. Guys like Kobe, KG, etc showed why it isn't necessary for everybody. Unfortunately you have guys like Green who showed all the athletic ability in the world, but were total boneheads. College would have done him well.
Green's much better off having skipped college. He probably wouldn't have been a 1st round draft pick otherwise.
This. Also likely wouldn't have really changed anything maturity wise, he needed to go through some struggles before he was going to appreciate being in the league.
It's almost February, so I suppose bumping this now is worth it. It's been half a season, and Green's averaging 13.7 a game, is the Suns second leading scorer (total, not per game, but with Bledsoe out he's their second option offensively),has a 110 oRtg, and has been a pretty good defender. He still doesn't really rebound, pass, or create off the dribble, but he makes far fewer mistakes than he used to, and has replaced the dreaded long 2 point shot with more threes, which is the biggest reason for his bump in efficiency.
Indiana was a perfect storm of bad situations for Green, he didn't fit that offense at all, had his minutes yanked around a ton, wasn't trusted by Vogel, and quickly lost his confidence shooting the ball. In Phoenix Hornacek has handled him perfectly, and he's playing a big role on the NBA's biggest surprise team this season, a team with the 9th best offense and the 12th best defense in the league. I don't think there's anyone who could have expected Gerald Green to be the second leading scorer on a top 10 offense.