I honestly think specializing in front or back end is a good thing. Sure, it does help to know both, but there's too much ground to cover for any one person to do well at all of it. I'm full-stack leaning towards front-end, and working on a personal project I know where the back-end is lacking. The front-end is pretty great but not as great as it could be if I could focus all my skill only on front-end.