Una due TFC,
I'm not sure the KL codeshare would be toast. Keeping KL out of DUB may be preferable to axing the codeshare. Besides I reckon only a matter of time before FR appear on the route, which may deter KL as the point to point portion of the service would be hotly contested. Not many of EI's big short haul routes left without an FR presence.
T5 is full to the rafters and there still are some BA services operating from T3, Expandion would be needed. IB services are only on 1 route and at most 2 gates are required . Vueling remains non T5, residing at 3.
I agree re capacity on london Aer Lingus routes;
Currently as an example BHD LHR combined BA and EI capacity is typically 9/10 rotations a day.
Typically let's say seats of approx 2665 a day( roughly mix of BA 320 and19's). Shifting all flights to 321 could result in (ei 212 seater) 6 rotations a day,7 to grow the route. 2 slots saved. Dublin potentially more if 321 and 330's used! And EI consideration of reintroducing business cabin quite aligned to the BA offer!