Shareef just needs a chance.
You cannot judge a player's abiliby based purely on statistics. I have followed Shareef's career all along, and I have a few things I gotta get off my chest.
Shareef was cleary a SF while in Vancouver. They had "the Big Country" Bryant Reeves(a moderate player who got pushed out not by his opponents, but his failure to control his weight) already inside, and the executives and staffs, still being criticized by fans for picking the slow center over the quick Damon "the Mighty Mouse" Stoudamire, had always tried to initiate the offence with him. So surprisingly, Shareef had to share the #1 option with Reeves, which meant he had to clear out of the way and stay many times on the top of the key. That was not a good position for rebounding.
Later things changed a little and he was forced to go back and forth between 3 and 4. True, he was still playing post even as 3, but his opponents were mostly 3 and kept him away from the hoop, out of the reach for many defensive rebounds. Back then he wasn't as bulky as he is now, and was quick enough to guard most of the SF in the league. But he wasn't strong enough to box out the premiere PFs then, so he usually didn't guard PF even as 4. Most of the time, he was guarding 3.
Someone mentioned "the golden age of Atlanta." What golden days?! That was when his stats took a blow, not due to his lack of ability, but the team's reluctance to play a player who was cleary not happy with them. His rebounding rose a bit because he was so cut out of the offense system that he had more time to go under and try to rebound. What is worse is that Atlanta, like Vancouver before, had no help inside. If you're not Rodman, you probably will have hard time rebounding when it's only you versus 3 opponents under the hoop. Atlanta didn't have anyone other than Shareef to score down low, so they basically didn't, which blew up much chance of offensive rebounds. Many times their forwards, again other than Shareef, got boxed out by their opponents and lost defensive rebounds. So continued Shareef's misery days.
Portland? You know what happened there.
My point is, Shareef is not a dominant rebounder, but at worst he is still better than average. He just never got a chance. Ever. Some say he couldn't lead, but he had NOTHING to lead. NOTHING. Of all the teammates he had in Vancouver, Bibby was the best ever, and he was a rookie then! In Atlanta, the team itself was lost and didn't have any time to pay any attention to Shareef. Portland just messed up and picked wrong talents to patronize. In all, a very few before him have had such a bad luck in teams as SAR.
The best trait of SAR, and sometimes I think it might be also his worst for his own good, is that he doesn't blame others. Never in Vancouver had he complained, whinning "my teammates suck," "I have no help," etc etc. He didn't complain about coaches, nor did he ever, EVER pointed a finger at the front office(whom I entirely blame the failure of Vancouver Grizzlies). He just played on, quietly. Ask anyone in Vancouver. They might not have any fondness for their old team, but everyone praises Shareef. He was not only amazing, but just as classy.
I saw one post about him becoming easier to defend if he was to get the ball all the times. Nothing could be further from the truth! This guy can pass, and he will! One of the things that he did so great back in Vancouver was drawing defense towards him just so that he can pass it to an outside shooter(but they just couldn't sink it...). Even as a rookie, he was better than any of his peers. He was so good that sometimes I had hoped that Vancouver hadn't drafted him. And I was living in Vancouver back then!
Nobody should question his scoring ability, and never should his rebounding skill be doubted. He just needs a chance to lead. I like Bibby as much as any of the players in the league, but given a chance, you might actually end up calling Kings "Reef's team" next year.