Sweetney's rebound numbers are actually almost identical to Randolph's. Sweetney's rebound rate last year was 16.3 compare to Randolph's of 15.9 and per 48 minutes on their careers Sweetney grabs 13.8 compared to Randolph's 13.2 (13.3 vs. 13.2 this past year).
I too have noticed the similarity between their first two seasons. At the same time Greg Ostertag's first two years are only slightly less similar to Sweetney's, so I'm not ready to celebrate quite yet. And, to be honest, I'm not a huge Randolph fan. He puts up 20 and 10, but he doesn't do anything else to make his team win: he doesn't make the players around him better on offense and certainly doesn't do so on defense. So basically he's a good player, but he's overpaid and you can't build a team around him. The reason this is relevant is because, like Randolph, Sweets is athletically and vertically (well really it's horizontal that's the problem: he's fat) limited. That said, I'd be ecstatic if Sweetney could go out and win a starting spot and put up 15/20 and 8/10. He and Frye might compliment each other nicely down the road, or we could perhaps use him in a trade for a long athletic guy who can defend (wishful thinking maybe).