QRA always used to wear immersion suits all year; silly not to.
I think there was a comment somewhere in the BoI about making sea drills more realistic so aircrew would be prompted to make sensible decisions themselves. Gets my vote. We used to alternate one 'easy' sea drill (say, off the beach in Cyprus) with one 'hard' one (Off Hartlepool in Febrrrrrruary). I recommend one night drill also.