Interesting thread.
I see the locos in three separate sectors:
1. Challenging majors on business routes, EZY seem to do this (ie LTN to CDG, ATH, EDI, GLA, BFS etc)
2. Opening up new destinations essentially for leisure, a la FR model (Newquay, BLK, Pau, Dinard, etc etc)
3. Taking over from the charter airlines on seaside flights (they all do this, but look at destinations like AGP, LEI, FAO, TFS etc)
Some locos dabble in all these market types, others concentrate on one or two. I can't see FlyBE taking on majors on key routes, and I can't see EZY flying to Timbuctoo. Perhaps the most consistent is FR, who won't fly anywhere without a 'deal' from the airport operator (unless it's to extinguish a weak competitor like MYTL at BHX).
If you look at the market this way, there's a huge amount of further growth opportunities. The ones that fail will be those who choose their markets wrongly, get their pricing wrong, or are under-capitalised. The ones who should fail are the dinosaurs like AF, but I can't imagine M Chirac would allow that...