At this point, I am going to be a bit shocked if difficulty doesn't top 200,000 by the end of the year (vs. the under 100,000 right now) - it might hit a slowdown for a bit when the existing A2/Alcheminer/Titan hordes get unprofitable, but even that won't stop it I am far too certain
A2/Alcheminers have reached break even at 10c/kw with the last diff spike...you can already see the effect...hashrate peaked at about 2.9 TH and dropped about 300GH since then. I bet you will be sticking around the 100-150k diff for a while as we hover around this equilibrium point of A2 going offline and A4/L3 replacing them.
Keep in mind the current gen hardware only increased efficiency x2...hashrate per machine has stayed around the same.