The situation with the E195 seems unfortunate, but can it be resolved?
How many airports are there which either:
a) Don't have a long enough runway themsevles to handle 737 / A319s
b) Don't have a large enough market to warrant the 3x weekly 737-800s that FR seem to be experimenting with - think all of U2's local hops are still daily+ from London?
c) Don't want to beaten into the ground by the more aggressive locos, but aren't sufficiently important hubs to generate regular scheduled links into LHR or LGW?
Flybe have always done well into France, so why couldn't SEN match many of their SOU routes? What are the ATC issues at SEN compared to other London airports - this seems to be something LYX was selling itself on, but SEN seems more able to tap in to a ready market.
I doubt that France alone would make a viable case for an airport. Let's not forget the UK too - certainly SEN-BHD could be much more attractive than STN-BFS if the timings were good (not just 2X daily like AB's STN-BHD).
Must be a few corners of the UK which can't get into the other London hubs because of slot restrictions - DND, Carlisle, Isle of Wight, Scottish Highlands & Islands, etc. Then add in places like BRN, and maybe a few niche markets in Germany & Scandinavia. Make a good offer to RE to move over from LTN........
It seems utterly bizarre to be talking about what is effectively going to be London's 7th international gateway, but I think there is a niche here which the other airports are either too congested or too expensive (LCY) to fulfill.