A quick couple of points:
Several posts saying fuel costs of A319 v 737-800 can't be compared, but on FR's slide show, this is the one area that EZ have lower costs. Is this down to hedging, rather than efficiency or load factor?
Re: VIE, MUC & ZRH - these may have failed for other airlines, but iirc, they have all been cited as examples of very high cost 'palace' airports by EZ & FR on several occassions. Could EI have been given an offer they couldn't refuse at these hubs? As previously mentioned, the market for NOC should be able to take one carrier, and FAO / NCE / AGP are all well established sunshine routes where seats will always get sold.
I'm still sceptical about this new base, but that is based on previous info from the likes of EZ & FR. If EI have got themselves a good enough deal with the airports concerned, especially with mgt @ LGW itself, maybe they might just prove a lot of us wrong?