Neptune is NEXT gen hardware for 2014. I don't see 14nm here. Yet.
But yes, i do expect that new hardware this year will be more efficient, just not by that much.
Consider this:
avalon, 110nm, 0.07th/s
bitmain, 55nm, 0.2th/s
jupiter, 28nm, 0.6th/s
terraminer, 28nm, 2th/s
neptune, 20nm, 3th/s
Well, you are forgetting one thing there, those rigs are priced very differently. The actual stat to go by is W/GH, otherwise you could have just bought more of the old equipment instead to get the same hashing power.
Even an old USB block erupter gets you 7.4W/GH, and the best equipment on preorder (Prosperro black arrow) gets you 0.5W/GH, "just" a factor of 15. Propably the margins on mining equipment are still insane.
Combine that with the fact that more efficient equipment can be made you can expect the vendors to roll out quite a lot. Maybe exponential growth will stop sometime this year, but i wouldnt count on it ...