Provide a Gnome Shell-like window overview instead of Compiz scale and Expo

I really like Unity (especially now that the global menu can be made always visible by a third party ppa). The only thing that really bugs me is window management ... Expo and Scale.

It's just unintuitive how both work.

First, why can't I combine Expo and Scale? Show all windows side by side on all screens? I don't think this should be the default, but when in Expo mode, it should be possible to invoke scale!

Expo on the other hand has some serious UI bugs too. Selecting a workspace by double clicking? seriously?
On my dual screen setup the 4 workspaces on the first screen are partially drawn on the second screen. Also clicks are not where they should be. Moving windows from one workspace on screen 1 to another on screen 2 is very unrealiable ... and many more bugs.

I switched to Gnome Shell because of the better (but also not bug-free) window management. Invoke the window overview and it looks like scale on Unity BUT you also see all other workspaces and can move from and to these workspaces.
You easily can switch to other workspaces, while still having "scale mode" on.

It's simply easier to manage windows this way.

Btw, I'm running gnome-panel inside gnome shell just to have a global menu ;-) works fine so far.