I think that the whole Saturn = Opel idea has some merit.
Look at Opel's product line:
Corsa - possibly too small for North American consumers (1.0-1.2L engine).
Astra - Should be Saturn's bread and butter vehicle (not the Ion embarassment). Small, affordable transportation.
Vectra - It's just a matter of time before Saturn gets Epsilon.
Meriva or Zafira - A better solution than the Saturn CSV.
But the most important part of this solution is the choice of engines. On the whole, mostly smaller displacement engines with a good number of Diesels.
In GM's line up, there is a glaring need for a family of smaller, more fuel efficient cars. This is where Saturn could step in and make a name for itself. By leveraging the already existing Opel engines and architectures, Saturn could distinguish itself as the "efficient car brand". That dovetails nicely with it's whole "touchy-feely" advertising style.
Saturn = small, cheap, reliable, fuel efficient cars? Sounds like a winner to me. GM can do this. The stock is already there is Europe.