He and Simon are 3rd- 4th rounders. They need to come back.
I love the enthusiasm of Tiger Fans, but a little perspective is needed:
Kyle Williams = 5th Round to Bills, and Kyle used to blow shite up in the center of the line all the time, Bennie not so much this past season.
Chad Lavalais = 5th Round to Falcons, and Chad was a badass his senior year, Bennie while solid is/was not that type of badass.
RJF = 7th Round to 49ers, and when he played he was a disruptive force.
Love Bennie and his play at LSU, but he is not a 3rd or 4th round selection IMHO, late round is more probable.
As for Simon, he is not NFL ready at this stage in his development.
Both need another year at the college level, do they stay - I don't know, but I think it would be wise for each to return for their Senior season.