I like floating panels, screen space is much better used in this way. I have seen daws with all windows dockable, and it seems that a lot of screen space is wasted for empty space or oversized controls. Even in Cubase 8 the dockable media bay and vsti rack is a waste of space to have it open all the time, although it is very handy when browsing sounds.
I think all panels should remain floating, at least as an option. I would hate to have everything dockable.