Mesa's business model is to fly regional services on behalf of US mainline carriers. They may see some mileage in the model in Europe. Flybe has too many aircraft in the UK it would appear. Perhaps a fleet redistribution would be on the cards in the event of a successful bid.
What they have always struggled with to make money on unlike their LCC competitors, is their reluctance to push and increase ancillary revenue spends.
It is harder to sell onboard to business people on 40 minute flight to another UK city than when you have people sitting down the back for 2+ hours. Additionally their baggage requirements are less. Priority boarding is not such an issue when a lot of the passengers are business pax with maybe only a laptop case - embarkation and disembarkation on the Dash eight never take particularly long. If BE is to make money it needs to be on the fare. It is hard to do this when your fleet size is so large that basically you are diluting your own yield through having an excessive number of rotations between airports. The company needs to shrink the fleet or diversify the business model. The company does not have enough cash to renew the fleet which means that they are basically stuck with the current fleet of Dash + ERJ. The Dash is (in my opinion) not fit for anything much further than 1hr 15mins due to comfort issues so there is not much scope to change length of sector so as I see it, BE's path back to profitability is through capacity management and/or flying for someone else. The Embraers offer a bit more flexibilty in terms of sector length but the problem is that they are not cost competitive on longer routes vs a full 737 or 320. I think the Virgin feeder thing will be of limited scope - I cant see LHR allowing any serious number of Dash 8 or 175 rotations into the airport due to wasted capacity. Regrettably there is no easy option for BE.