The problem with LCY indeed is that it is a typical inbound airport. Back when I was involved in some consulting work I discussed the problem with three airlines that served or where interested to serve LCY from Germany (none of the routes materialized or still exists). You will always have a reasonably full aircraft on the inbound morning run and the outbound late afternoon / evening flight(s). However, quite often you will have a literally empty aircraft on the morning return flight and on flights at noon time if you don't give tickets away. Add to this the high fees at LCY and the high costs of marketing in a market where five airports compete,, and it is quite evident why it difficult to build a route successfully as a smaller regional operator.