I for one don't understand all of these comparisons to Marion. Their playing styles really are not all similar.
I think it is because people think of guys in terms of being an offensive player, a specialist role player, a defensive player or an energy guy. This goes from the NBA to college to pick up at the Y. The energy guy is always the one seen doing the little things to help win, getting lose balls, rebounds, playing good d, put backs, doesn't turn the ball over, etc., but traditionally they are not scoring 15 ppg+ with these tactics.
I think that it's so rare to see someone be a high level player but still an energy guy at heart that it's hard to make comparisons when they're good. So I mean if your choices are Kenneth Faried, Dion Waiters or Marion, you're going to compare him to Marion even though it's not a great comp.
I don't think AG will be a bust, I just think he's like the 12th guy I would draft. Getting him at 5 seems like a waste.