,Frank Hileman wrote

Consider the "metro style" rules for applications. Is it worth paying lots of attention to the metro profile? It may disappear soon. We have no way to know.

Isn't that always the case?  Technologies progress.  People used Prototype, now they use CoffeeScript.  What will it be next week?  People used tables, then only divs/spans, now grids and flexbox, what will it be next week? 

This is why the core of a good developer should be fundamentals.  If you ask me to RoR, I can pick it up in a day or two.  If you want me to ASP.NET MVC, the same thing.  Was up and running with WPF in a few days coming from scratch.  HTML/JS -- literally felt comfortable in a few hours.  Haskell, give me a week to be comfortable.  Learned QT (from w/ C++) in a couple of days.

Sure I'm not a language lawyer in that time, but I'm "early" productive in that time, and learning.  But I've built the foundation and I supplement it with these languages and frameworks.

If you feel like you're on a treadmill, it's because you have no foundation.