I don't think he'll be here for 3 or 4 seasons, but it will only benefit him to stay one more year. He could be a lottery pick if he keeps it up, as opposed to maybe a late first this year, plus he would get another year developing, gaining experience, and adding muscle.
Bottom line he would probably gain more money and be a better basketball player if he stays 2 years. I think he is definitely an NBA talent, but needs to learn a lot before he is ready.
Next year if we have a frontcourt consisting of Gathers, Sampson, Harkless with Gift off the bench, Moe will impress even more being at his natural position SF.