Case in point...

Look at this example of an application using the Metro UI:

There is no discernible indication that the "Pick feeds" text is actually active and invokes an action. The link actually brings up a set of podcast feeds but floating the mouse over what seems to be a title has the effect of an almost indistinguishable darkening of the colour. I suppose in reality that the choice of float-over colour was one made by the application designer but when moving to a totally new user interface model, there should be a rather more noticeable change.

I'm all for subtlety but there is a limit below which subtle becomes obtuse.