Why wouldn't they be after exclusive publishing rights to series like HP, LOTR, DC, and others? MK is huge but I think the franchises are just as popular and could a boon to the service ( no pun intended).
because they don't want more IPs that they don't own.
What is the value of Batman and Superman when they have a hard time getting people to work on MechWarrior, Shadowrun, Crimson Skies, Killer Instinct, Crackdown, Banjo-Kazooie, etc?