LTNman
I know you always deny being anti-SEN, but your post looks more like wishful thinking to that end rather than any thought out projections.
Firstly, you could be right and easyJet might simply replace some existing routes with others over the next couple of years. On the other hand they may find that nearly all the existing routes perform satisfactorily after a period and increase the number of routes and based aircraft. Such a scenario seems equally possible surely.
Secondly, it's rather sweeping to say that "there will be no real demand from other airlines...." just because STN may be under new ownership by then. Would you say that about LTN then in those circumstances?
Lastly, on what basis do you state that "IT flights from Southend will still be very limited with no real increase on next year." ? SEN's natural catchment area is well populated by those most likely to take IT flights, so there is no reason to assume that it might not be serving half a dozen destination on that basis after a couple of years, rather than the one or two anticipted so far for 2013.
The truth surely is that no one knows how successful SEN with prove to be in the medium to long term; it probably very largely depending on if (I don't feel able to say 'when' any more in that context) the UK economy recovers to a meaningful extent by 2015. The airport's potential is still evolving and it's not expected that the extended terminal will be "maxed out" as you put it until 2 mppa is achieved and it will require considerable growth beyond 2013 before that landmark is reached.