Didn't Durham Tees Valley - Dublin route get around 80,000 passengers per year?
If Carlisle airport & Stobart/Loganair can make that work with a Saab 340, I'm sure someone could make that route work from Durham Tees Valley with a larger passenger catchment base meaning the larger aircraft would be more viable.
Lets say Flybe/Eastern airways used a Saab 2000 and fitted in 10 - 12 return flights per week around the Aberdeen schedule flights. Those type operations could carry 50,000-60,000 passengers per year on a Durham Tees Valley - Dublin route.