EZY aren't keen on basing an aircraft in ABZ due to the crewing costs, i.e hotac etc.
That hasn't stopped them doing the exact same thing at INV.
Besides, as it stands a lot of passengers are flying abz-lgw-alc, so for them basing an aircraft in ABZ to do a long holiday sector doesn't make much sense.
There's quite a bit more that can be done than just ALC... Besides the suspect sun routes perhaps a few city routes would be in the frame. Purely hypothetical sadly but surely someone will take the plunge at some stage? A one million increase in pax numbers in just 4 years has got to attract some interest surely?