I think there is a gap for a small jet to fill the hole between an A319/320 and the ATR for EI. Whether they would be operated by Stobart or Lingus is another question.
As for the next EIR routes, its a difficult one. There isn't that many more they can go to. Liverpool, Luton, Stansted, Newquay is about it!
I would like them to try MME and DSA again. Used to fly these routes regularly and I will say that they weren't given a proper chance. Whether that is EI or Peels fault I don't know. There was little to no advertisement of the routes.
At the time RE were having a nightmare. The start of the EIR franchise was rocky. I used to be on the MME flight on a weekly basis - initially the loads were fairly good for a new route 45-60ish. Then the rest is down to RE. The schedules were terrible. It felt like each week they changed the operating days and the departure times to suit their network expansion and lack of aircraft. They tried to progress to quickly. By mid summer when they had opened other routes and stretched the fleet too much. Cancellations after delays after delays. I'm not surprised that people left it and towards the end there was usually only 20 on board. Similar story at DSA.
I still think that these airports could support a good, daily 42 service at least to start with. Stobart have sorted the old issues out. Infact, I've gone nearly 200 sectors without a cancellation (other than horrendous weather!). Even delays are pretty infrequent - I would say 3 times out of that 200.
During the MME days I may have flown 60 sectors, there was on at least 4 occasions I recall being cancelled and driving like hell to NCL to catch the FR. Delays were also much more common - quite regularly an hour or so late.