If Austria, rather than Prussia, had been the power that had unified the German states in the 19th Century and how would the Austrians have done things differently?
Off the top of my head I imagine that Catholics would be more influential in this alt-German Empire and their wouldn't be as much in the way of anti-Catholic Kulturkampf. A more pro-Catholic Empire would alienate the significant protestant populations in Germany, but might make it easier to hold onto any formerly Prussian Polish territory that the Empire inherits (as well as the Austrian Polish territory).
Another main issue would be the numerous non-German territories in the Austrian Empire. Would the German Empire be forced to embrace a more tolerant position towards minorities? Would a similar situation to the Dual Monarchy arise, with the Empire reformed into a German-Hungarian Empire, or would the mostly non-German parts of the Empire be broken off and united under a separate Hungarian/Polish-Hungarian Empire under a different Hapsburg?