Regarding the multistep stuff you mention, Gabriel will have to tell how the behaviour will be, but I feel the question is somewhat missing the point of this feature. The point being these multistep actions that you mention can all be reversed, meaning: If you go three steps up, you can go three steps down, if you change your mind.
The interesting part is all the functions that are irreversible. Deleting the wrong track, hitting RMX by accident, deleting a page, the RND function etc, etc. This is where one level of undo will shine.
And no, it does not do anything that PLAY would not be able to do, but PLAY is something that you use consciously with a purpose. Like, you probably wont use PLAY because you are thinking that your next move will be accidently erasing the wrong track.
Is it more clear now?