I'm not at all a Java fan, but how does shifting from Java to Scala help you scale easier? Scale what?
As to hiring better developers, I've never found that the language makes a difference in finding good developers, it is just that the smaller the community, the easier it is to find the good developers. I know many brilliant php, java etc developers but they are much harder to find when doing a blind job search than lisp, smalltalk etc ones because the community for php, java is so much larger.
I experience the same thing when looking for css/html people. It is hard to find the good ones because you get buried under a mountain of mediocrity when you go looking.