I'm wondering if any party or politician in Germany has called for the President to be directly elected by the people. The mere fact that such a figure would be directly elected would hardly mean that they would have to be a powerful figure like in France. Austria and Ireland have shown this to be the case. I'd love to see directly elected presidents in Italy and Germany. I know that in Italy the right wing National Alliance supports this idea.
I'm guessing that because the Weimar Republic had a directly elected president the post-war feeling was that the concept was to intertwined with the Nazi takeover. Hindenburg named Hitler chancellor, and Hindenburg was directly elected, so that somehow discredited the whole concept I suppose.
There give some politicians who want this, but this are not many. The problem is the German President have nearly no power and is a function which only for representation. When you elect him directly then he needs more power and this changes the complet system. I think we don't need a president in Germany. The chancellor can make it too.