Jet2 at the city would be nice, but as pointed above, there wouldnt be any stands for them to use. The airport is already crowded with the stands used up each night, and both Manx2 aircraft on the Victoria Apron.
This will only get worse when the Baby moves in for the STN flights, probably a Flybe will be remote parked too, the airport dont seem to be doing anything about it either.
Also, as pointed above, with the night curfew, cargo ops from Jet2 wouldnt be possible at the city, but it is a massive form of revenue for them. Some of the BFS-LBA flights, if they get the usual 60 or so pax on them, its just extra money, and a way to keep linked up to their head base.
Same for Titan, i spoke to the head of their fleet a while ago, theyre holding onto the 146s and older 737s because there isnt really anything else thats newer and can take on the combi roles that they do