Had it been 2 aircraft out of 8 dedicated to medium-haul (short-haul was only undertaken to replace AOG and then only as the programme permitted) I would agree that it would not have been a small portion. Canadian Affairs is IMHO more lucrative than clawing back contracted out seats, so is not really a problem (and allows 'seat swapping' deals that keep contracted-in seat rates reasonable.) Over capacity in summer in Scandinavia is a problem when the aircraft are hived off to the UK (who can make more money/less loss from them,) but may be a good way of the group making best utilisation of its assets.
Lets just wait and see what happens instead of trying to second guess decisions made by the tour operator (not the airline) based on information we don't have.