This seems to have been a co-project and publishing together rather than selling the rights. Most likely it seems that Blizzard wasn't able to develop console games and was a strictly PC, so that's why they needed a partner.The contract will be crafted for wc3 only, not the whole Warcraft franchise.
For example by letting EA distribute wc2 on PlayStation (back in the 1990s): Blizzard did not allow them to publish and sell every Warcraft product...It was only for wc2.
And also Blizzard doesn't seem to be willing to sell the rights to distribute any of their games. We're likely never gonna see another StarCraft game, and Blizzard has no intention of selling the rights to it.