Gustav II Adolf toyed with the idea of declaring himself protestant Emperor. What if he had lived, seen a good victory at Lützen, had an heir and declared himself Emperor? Sweden is too poor and desolate to keep such a title for too long, it will pass to the Prussian King sooner or later, methinks, but perhaps Sweden would gain provinces from Denmark sooner, maybe the Wasa dynasty would remain in power and Sweden would be larger and stronger by the time of the Napoleonic wars. Considering OTL though, it would probably just mean more disastrous wars in Germany, no? What do you think?