Okafor is a victim of the modern obsession with stats.
I think it's less about stats and more about the current trends in the league. Teams more and more get their points from the perimeter, generated by their guards, and teams expect their centers to account for most of the defense in the restricted area. As a big man, if you can't make life easier for your team on defense and dominant the boards, you'd better be able to stretch the floor and defend multiple positions, otherwise you're "obsolete."
Makes it tough for a guy who is weak defensively and who excels at creating offense inside 15 feet, without the range or agility to play at power forward.
If Okafor came into the league back in 2010 / 2011 when the Lakers were still dominating the league via their super-tall Pau / Bynum / Odom lineups, you wouldn't be hearing about how disappointing Okafor is and how he's just another Al Jefferson.
For that matter, if Al Jefferson had ever gotten to play on a decent team during his prime, you wouldn't be hearing that Big Al comparison as a negative.
Honestly, I'm really hoping that New Orleans finds a way to pair Anthony Davis with a dominant young interior presence so that the vogue in the league shifts back toward big men who create matchup problems with their scoring inside. Maybe Utah can shift the discussion if they can get a decent point guard and win 50+ games with Hayward / Favors / Gobert.
I like that small-ball and perimeter scoring have become much more popular. The game benefits from an emphasis on versatility, ball-movement, spacing, and so on. But it goes too far when people decide there's only one way to construct a team that can win.