If easyJet chooses Airbus it will probably be the beginning of the end of the low-cost airline.
The business plan of easyJet is more fragile than Ryanair because they chose to operate from main airports and for this reason its costs are very high. Moreover it will be difficult to grow 25% per year with 'slots war' in Gatwick, Amsterdam, .... The strategy of easyJet is not as clear as Ryanair which chose to base its competitive advantage on prices. And if you add the costs of the mixed operation of two different aircraft or the change in a all-Airbus fleet it will be very very difficult.....