Earlier quoted context omitted.
Certainly, but an unrestricted code signing certificate would be quite useful too (until they are revoked)
Mmmm... maybe. Okay, let's say you can sign code as anyone, even Apple itself, and create rogue apps. Now, how do you use that information to compromise iOS devices? You probably won't be able to get it in the App Store, and the iOS devices won't install from anywhere else. You could make an Ad Hoc distribution package, but for that you need to know the UDID of each device and convince your victim to download the rog…
So (again, assuming no revocation), you could set up a web based alternative app store, or re-sign cracked apps/games, or just enjoy being able to run code on your own devices (and distribute to others without going through the app store) without maintaining the $99/year subscription, or you could start linking/redirecting unsuspecting web browsing users to install malicious apps (would only need 1 confirm click)