The tradition of undersized 4s becoming second-round steals continues. In recent years, we've seen Brandon Bass, Paul Millsap, Craig Smith, Leon Powe and Carl Landry establish themselves as quality frontcourt players even though they were drafted after the first round.
Mbah a Moute is more of a lanky, athletic guy than the others, but it's the same idea -- he didn't fit the prototype of an NBA 4 man, so he went later than he should have.
Mbah a Moute is middling at best as a shooter and won't score in the post, but he is athletic enough to be a very effective garbage man and can defend three positions. He has been starting while Charlie Villanueva is out injured and has played well enough that he seems likely to keep the gig even when Charlie V. returns.