Talking out of my rear end here as I do not know his personal situation, but I too wonder if he isn't kicking himself a bit. I don't think he played as much as he wanted to his last season in Norman- and he was a teenager so likely very emotional and possibly had an over-inflated view of what he would be as a college player. Perhaps he was frustrated and wanted to go somewhere he thought he'd be able to play more consistently and/or have a bigger role.
As it turns out, he probably would have had the same role at OU as he does at Monmouth; maybe not quite as many minutes, but he would be in our rotation without question. And I agree that he would almost certainly be the sixth man on this team over whoever you consider it to be now. Long story short, he could have made one of the better teams in the country even more dangerous and had a shot at a Final Four instead of playing in the NIT for a mid major.
Now perhaps he just didn't like Norman or Kruger or his teammates or the school and he's happy as can be to be out and playing for Monmouth. If it was based on those "happiness" factors than I don't begrudge him one bit and I imagine he has no regrets. But if he left due to purely basketball reasons, then it certainly appears to be a decision made in haste.