From Easyjet's perspective the only route that will be impacted by Aer Lingus winter flying programme is BFS LGW. Why would easyJet need to add extra flights to any routes outside of London for competitive advantage? The capacity in place ex BFS last winter on competiting routes was was overlapping on AGP and ALC. They were not high frequency and there was about enough pax to fill easyJet's flights.
While easyJet have said they will step up London routes (which seemed to be a response to EI rumours) in frequency, there could still be increased by non based aircraft
I would however, expect next summer to see easyJet respond agressively on AGP and FAO routes to EI's plans.
EI-BUD