I'm not going to 100% say that control is the reason Apple is doing this. I'm sure that they do genuinely want a way to quickly quash malware, worms, etc...

But we've also seen that Apple is clearly willing to use security features to ban developers that stand against them, so I don't understand how people can be so confident that they wouldn't be willing to use this feature in the same way, even if they did internally think of it as primarily a security tool. It would be very consistent to how we've seen app signing evolve from a pure security feature into a contract-enforcement tool.