Is a Move a Good Thing for the Kids?

A decade ago, after moving around a lot before and after highschool, I was fed up with getting to know a new place, and in particular new people. I felt like I needed to stay put, to grow some roots. So here I am, a decade later, still in Berlin where I moved to after my studies in London. One flat purchase and three kids later. Many friendships and a couple of job experiences richer. But when has one really arrived? All of my foreign friends agree that we will always remain foreigners, we will never learn the horrible conjugation of German grammar perfectly. And in times of short-term contracts and globalization, I have realized that most of my friends are again in different cities and countries, as they have moved away. I feel torn at the moment, between wanting to leave myself in search of better job prospects - and staying in what I know. And more importantly perhaps, I am ridden with insecurities as to what would be the best for our kids (6, nearly 5 and 1.5). Is a move a good thing, if the number of active languages would increase from three to four? If dad and mom may at some point be working? If it means yet another kindergarden and school, possibly in a new language? If one is not certain for how long one would stay? Is one's own fulfillment, and perhaps happiness, or the stability of the kids' surroundings more important? Is it worth it to take the risk? A lot of my friends, many who have moved also to developing countries, will surely be able to provide wise insights on this, and I would welcome as many wise words as possible.