Why absolutely, positively no Embraers (or Bombardiers) for GF? If it makes economic sense then why not? Of course, I would love to fly the Boeing 747-800, failing that the Airbus A380 is a satisfactory substitute . . . but I don't think these things are in the cards for GF. And from what I understand, the economics of the A318 are not attractive compared to Embraer and Bombardier products.
Does it make sense to be flying around half-full/half-empty A320's or A330's, or having to drop fares just to fill them up? Regional Jets may just be the proper ingredient for GF to open up new routes, cut losses (make profits) and create better job security.