For the betterment of all players, they should all stay for additional development in college.
In Gordon's case or anyone else's in this draft, if they stay, yes there's a chance for further development. However, there would also be a new draft class the following year to compete with.
Look at Terrence Jones, I believe he would have been a Top 3 pick in his freshman year. He came back for his sophmore year and was a mid-first round pick.