I thought that Embraer shelved the stretched 195 due to lack of interest and concerns over its range.
The A320 NEO's non-retrofitable advances will not be enough to fend off Boeing once the 787 is out of the door. I reckon that Boeing have track position to pit, put on new tires and emerge well in the lead.
My unsubstantiated and circumstantial knowledge suggests that the 737s problem has never been one of efficiency, but upfront costs. In many ways the NG is better and more efficient performer than the A320 series, but with the current trend of relatively frequent fleet renewal it doesn't look so good.
I wonder if they'll soon be selling heavily discounted 737s on the back of commitment for it's replacement.