I disagree with some of this. However I do approve of the overall message - be good, if not great, at one thing (or more things) in particular.
Edit:
If you wish to specialise in one particular area - that's a great thing to do. But equally as important is not to limit yourself solely to a single language or framework as the experience gained from comparing different languages and their best practises, syntax, pit-falls means you become a better developer overall in my opinion.
Well you can do this really easily in language X so how can we do that in this language OR can we actually use language X instead?
TheSheriff
Co-Founder, Founder, Entrepreneur & Problem Solver