Er, can't you push a lot of information to the lock screen already? That's an API I thought all developers had access to. I only let IMs, e-mails, and facebook onto the lock screen on my touch but I'm sure you could news or live feed the heck out of the lock screen if you wanted to? There's got to be an app for that.
When I had a jailbreaked 4.x touch, in the end, this is the only JB feature I kept enabled. It would be nice to see a faster toggle screen somewhere. I don't think it would be terribly useful for music controls though - you're never more than a double tap and swipe away from those at any time.
As of right now the lock screen is just notifications and its all or nothing. You can't deal with individual items. And I'd like to see my whole calendar and reminders for the day so I know what's going on at a glance without actually going into my phone.
And the weather. It drives me completely crazy that weather can't be seen on the lock screen.