Looking at the classic mode screenshot, there are a few questions:
- where is the workspace switcher (i.e. visibility is still zero)?
- can it be customised (can components be moved from panel to panel or from place to place on the panel)?
- will it be usable on a computer that has no 3D acceleration?
Looking at the state of extensions, the answer to the first one is probably "there won't be a fully functional one". If nothing changed in the way components are laid out in Gnome 3, the answer to the second one is probably "this cannot be done". Don't really know how good emulated 3D will be by the time 3.8 hits released distros. Last time I checked (F-17) it was too slow and was burning CPU like there was no tomorrow on my VMware VM.