They aren't necessarily trying to take Pooh from Disney, just regain rights to a character that was developed by a family member. I think the loss of Pooh would be great for Disney....then they could push someone (Mickey *cough*) else to take that place that they've allowed someone elses creation to take.
In my opinion, they've put too much emphasis on Pooh and his supporting cast and not enough on Mickey and co. When I think of Disney, it's not Pooh that I think about....
I think Disney made some shady deals to acquire the Pooh rights that they have, basically leaving the two other parties that own partial rights with nothing. I'm not a Pooh fan tho....if he goes, he goes....any other company that could possibly acquire him later wouldn't have to do much marketing to keep Pooh in the public eye. Disney didn't develop the Pooh look, it was already set so the whoever-would-be owners wouldn't even have to change his look or anything.