One issue that should be considered is the fact that the F35 is single engine. This is not a major issue in a combat scenario I would think, but in northern Canada patrols the air bases are few and far between. A multi-engined machine will save itself and it’s pilot whilst the best outcome for a single engined fighter pilot on northern patrol would be the pilot able to share his survival rations with a curious polar bear. For N.A.T.O. commitments a bleeding edge fighter would be fine, either the Saab Gripen-E or the F35.