I know the Germans out there may not like what I have to say, but frankly, old Franzie has been unfit to rule for years now. The man is (or rather, was) ninety-six years old and has been suffering from dementia for nearly a decade. He should have given up his throne a while ago.
Regardless, he will surely have an eminent place in history. When he inherited his throne, his land was divided into squabbling principalities, and through his efforts, a united Germany stretching from Oldenburg to Königsberg to Vienna to Baden was born. This unification can be compared to the consolidation of HRE authority under Ferdinand IV in the 1830s. His leadership in the Great War prevented the Russians and French from dominating the globe. The atomic bombings of Grenoble, Kursk, and Brest in June 1938 brought peace to the world and eliminated the hateful ideologies of the Franco-Russian axis in a crushing victory not seen since his forebears' success at Jena.
Americans, Chinese, Russians, and German Republicans may complain about how Franz IV held absolute power until the day of his death, but keep in mind the liberal reforms that Germany's made since the 1970s. Plus, of course, Karl, though aging, is an ardent supporter of these reforms. I imagine we'll see more and more reform in the future.