I think Tagron has summed up the situation accurately as things stand. There was a proposal to certificate a 15 degree slew on the 24 climb path (a la SOU) and I think that the fact this was no proceeded with suggests the current restrictions on 24 are not a significant problem to easyJet. I believe that there are no obstacles within the 06 climb path which materially affect Second Sector Climb performance for the A319.
It is not possible to offer greater TODAs than the current 1799m due to the runway width, as smallpilot rightly says. CAP 168 stipulates than the declared TODA for a 37m width runway cannot be greater than 1800m. Strip width considerations preclude the widening of the runway as a solution.
The A320 is a very good performer from the SEN runways and the A320neo would be even more so. If easyJet remain committed to SEN perhaps we shall see those at SEN once they become available.