For me, the only thing we can do is stay in
Whether we are in or out, we are going to be influenced and controlled, at least to some degree, by Europe, as we are by the US, China and other parts of the world. We can't survive as a single entity unless we want to steadily drop down all the global league tables - something that, as an aging post-industrial nation we will do anyway, but just not as fast as we would if we were to go it alone. By aging, I mean in terms of both our population and status as the 'original' industrial nation.
We would do better to be in the Union, albeit not tied as closely as some are, and work to improve and develop that Union from within.