I think 2016 will be a challenging year for Luton. Once that is out of the way we should see some marked improvements.
As for Southend taking substantial passengers from Luton, well that's what they did at Stansted when Easyjet moved aircraft to the east coast although I agree I can't really see it happening at Luton.
I think easyjet will hang in there at LTN but with their HQ within the CTA the directors, route planners and annalists will see first hand on a daily basis what is happening at Luton.