Personally, I actually like that particular suggestion. Once again, the question is, why shouldn't it apply in the same way to employees of the crown? Employees of the crown typically serve abroad for a period of time and they come back; sometimes they'll be over there for a while, and then we're talking about their children who are abroad for a period of time.
I have difficulty with citizenship being decided based on a type of employment as opposed to the principles, and you're establishing principles that would pass it down generationally but in different contexts. I like the residency part, and perhaps that provides the parameters, but I'm not comfortable with the parameters that a certain type of employment guarantees you these additional privileges.