So, if SEN can't attract major new airlines it should focus on accommodating the major airline it already has. EasyJet have shown faith in the airport, but if the tale about their pulling the fourth based A319 because of on-going taxiway issues is true surely that's what SEN should focus on, along with offering improved facilities within the terminal.
The Amsterdam route has been a great success and could probably bear additional rotations. There are several Mediterranean destinations which would very likely be successful for EZY, not least Malta. It will be interesting to see how their new route to Mahon goes.