I think NCL will see an upgrade definately on the EK route. it's just a matter of when not if. EK are a massively expansionist business, even with the crap dubai is going through, it's still got 140 aircraft on order with 50 options. The other big point to remember is the A332s are the oldest in the fleet with the oldest cabin interior, so they're likely to be the first to go (some of them are approaching 11 years old!)
The question is what to; my bet is the A350s will replace the A332s and the A340s in the fleet. And NCL will be upgraded to either a 772(poss LR) or 77W. If NCL gets the runway extension that was in the 2016 dreambook, then they probably will get the 772. If not I think EK will hold out for the A350.
Of course, in my mind, the goverment should be looking at things and saying heathrow is full, get a high speed railway network that covers the whole damn country (not just up to bloody leeds) And develop Newcastle as a northern hub (but that's just wishful thinking)