Lots of truth here, but I'd point out that the one thing you don't want is someone who only knows one language well. They haven't had practice thinking in diffe

Lots of truth here, but I'd point out that the one thing you don't want is someone who only knows one language well. They haven't had practice thinking in different headspaces and they see things interacting from only one perspective. Unless you have someone managing them who can see from all the perspectives you need and ensure that the developer doesn't break compatibility, you're better off finding someone who isn't a one-trick pony.