Well, people obsess about him here because he's been a highly touted prospect since well before he entered the NBA. For a franchise obsessed with finding the next "star" a guy who is as young as Okafor is and as highly touted as he was, while also having a fair chance to be available, is going to be a big target.
Personally I think that's a wrong headed approach though. Okafor could've been a much more impactful player 25 years ago than he will be in the next decade. His game just doesn't mesh with the direction of the NBA, and he just has too many limitations and flaws to be a superstar in a game that is becoming increasingly dependent on versatility.
Okafor is an ELITE low post scorer. That skill will always have value, and he'll be able to make a career out of it, so I'm not saying he's terrible or anything. But he's just so limited in every other facet of his game I can't see him ever developing into some kind of superstar. While he is great on the block, he has very limited range on his jumper, while also being just outright awful on defense. He'll NEVER be able to even switch onto today's 4's without getting burnt. Therefore, you'll need to find a 4 who can not only shoot the 3 but can also defend the paint and the perimeter, while also being able to be effective with limited touches on offense. Not a whole lot of guys around the league who can do all that. Having Okafor on your team leaves you highly susceptible to bad match-ups
More than anything though the problem with Okafor is that, on top of being a poor defender and below average rebounder, you can only get the most out of his elite skill by basically running your offense around ISO post ups for him. Now this is a problem, because not only does it bog down your offense as a whole but Okafor has not shown an ability to run an offense through the post ala Greg Monroe. If your gonna feed shots to a post up big like him, that guy really needs to be an elite passer to make it work, and Okafor just isn't that. He can make an obvious, easy pass but far too often he takes on a double team and tries to score instead of finding the open man. If he doesn't have the ball in his hands on the post, he's basically useless.
Even if your an elite inside scorer, the lack of high level passing and rebounding skills combined with his putrid defense, lack of any versatility and questionable personality is going to keep him from reaching that magical "star" level. To me, I probably wouldn't trade for him even if it was an "underpay" simply because he requires designing your whole offense and defense around covering his weaknesses and highlighting his strengths at the expense of the other players and TBH, he's just not good enough to justify doing that. Now or in the future.