From what I heard at a conference earlier in the year, NATO tours are going to be coming round more often and in certain areas are now a priority. I believe this stems from Libya when the UK tried to take up key posts in HQs various and were told no, you can't gap them and then swan in when you feel like it for the Ops.
Seems a little disingenuous given the UK contribution to AFG, which many of those nations being critical of the UK conveniently forgot that was the biggest NATO op ever!
However, as a result, if the conference speakers were correct, you will need a NATO tick in future if you are to be seen as competitive on the boards.