I don't think Simmons or Ingram is some kind of franchise savior. Simmons is a great fit as a 4 in the modern NBA though because he can guard inside and on the perimeter, rebound, handle the ball like a guard, and score inside. Even if he never develops a reliable jumper, he is still going to be a very valuable player. I see him as a better version of Draymond Green who can create offense on his own much better than Green.
Summary: The former Wake Forest transfer was not even on my NBA Draft radar prior to the NCAA Tournament, but due to VCU's magical run to the Final Four, he suddenly drew a lot of interest and deservedly so. He has good size and a talented enough inside/outside game to draw second-round looks. If he goes undrafted, he will certainly get a chance to prove his worth in the summer league and in some team's training camp.
Player Comparison: Brian Cook. A below-average athlete by NBA standards, Cook has stuck around in the league due to his ability to step out and knock down jump shots. Skeen has that weapon in his arsenal and also the strength to overcome his lack of size. I would not expect Skeen to be to anything more than a seldom-used role player at the next level like Cook.