Actually, holding the volume rocker button and the mute switch are not the same.
The rocker switch mutes everything, and you have to have the iPad unlocked for it to work (unless you are already playing music while its sleeping, of course). The new Notification mute switch only mutes system notifications and alerts. If you are watching a movie, just flip the switch and your movie sound wont be interrupted with twitter updates, E-mail notifications, etc..
Just a double-tap and a swipe, and youre at the rotation lock button. They are not removing the ability to lock the rotation, just moving it.
To use the new Mute Switch you dont have to unlock the device to disable notifications alerts. And there is also no reason to use the rotation lock when you are not using the device.
And, it will work the same way as the iPhone.