What if somewhere between 1714 and 1795 the Austrians managed to get their dream trade of Bavaria for the Austrian Netherlands? Perhaps this happens after the Wittelsbachs die out in 1777? Or they win the War of Bavarian Succession?
The appropriate time for the exchange of territories would have been in 1778.
On 30 December 1777, Maximilian III Joseph, last Elector and Duke of Bavaria and last male representative of the Bavarian branch of the House of Wittelsbach, died leaving no children.
The Elector Palatine Charles Theodore had a legitimate legal claim as heir, and succeed him as "Lord of the seven countries".
When the Bavarian succession came up for grabs in 1777, Joseph II saw his chance to compensate the dynasty for the loss of Silesia. In January 1778, on Joseph’s instructions, in agreement with the heir Charles Theodore, Chancellor Kaunitz compelled the Bavarian ambassador in Vienna to accept Austria’s demand that Bavaria be exchanged for the Austrian Netherlands. Charles Theodore had dreamed of building a reign in the Burgundian Circle (an Imperial Circle of the Holy Roman Empire), with a planning to exchange of Bavaria for the entirety of the Austrian Netherlands. Although the Austrian Netherlands was a wealthy territory, it was a thorn in side, devouring military and administrative resources. Acquiring territory in the German-speaking states was an essential part of Joseph's policy to expand his family's influence in Central Europe.
Joseph understood the problems facing his multi-ethnic patrimony and the ambivalent position the Austrians held in the Holy Roman Empire. For Joseph or his successors to wield influence in the German-speaking states, they needed to acquire additional German-speaking territories. Acquisition of Central European territories with German-speaking subjects would strengthen the Austrian position in the Holy Roman Empire. As far as Joseph was concerned, only this could shift the center of the Habsburg empire into German-speaking Central Europe. This agenda made dispensable both the Austrian Netherlands (Habsburg territories which lay furthest west) and Galicia (Habsburg territories which lay furthest east). It also made the reacquisition of German-speaking Silesia and acquisition of new territories in Bavaria essential. The Bavarian succession crisis provided Joseph with a viable opportunity to consolidate his influence in the Central European states, to bolster his financially strapped government with much-needed revenue, and to strengthen his army with German-speaking conscripts. Supremacy in the German states was worth a war.
For Frederick II of Prussia, Joseph's claim threatened the Hohenzollern ascendancy in German politics, but he questioned whether he should preserve the status quo through war or through diplomacy. Empress Maria Theresa, who co-ruled with Joseph, considered any conflict over the Bavarian electorate not worth bloodshed, and neither Maria Theresa nor Frederick saw any point in pursuing hostilities. Joseph would not drop his claim despite his mother's contrary insistence.
Frederick Augustus of Saxony wanted to preserve the integrity of the states within the Empire, no had interest in seeing the Habsburgs acquire additional territory on his southern and western borders. But his dislike of Prussia, which had been Saxony's enemy in two previous wars, Frederick Augustus has not provided any concrete support to Frederick.
France became involved to maintain the balance of power. The French foreign minister, Charles Gravier, comte de Vergennes, acted as an intermediary in the War of the Bavarian Succession between Austria and Prussia, which he feared could trigger a major European war.
Two (among the many!!!) would have been the conditions for the exchange went fine:
1. The marriage between Charles Theodore of the Palatinate-Sulzbach and Elisabeth Auguste of the Palatinate was not a lucky one. The couple largely lived apart, each one taking lovers of their own; one child, a son, christened Francis Louis Joseph (Franz Ludwig Joseph), was born on 28 June 1761 at Schwetzingen Castle, twenty years after their marriage; but the long-awaited son and heir to the Palatinate died just one day after his birth.
IF Francis Louis Joseph had survived, the position of Charles Theodore would be considerably stronger against his own relatives, his wife Elisabeth Auguste and his sister-in-law Maria Anna, widow to the Bavarian prince Clement Francis de Paula, against the widow of the Elector Maximilian III Joseph of Bavaria, Maria Anna Sophia of Saxony, against the Electress of Saxony and Max Joseph's sister, Maria Antonia of Bavaria, and mostly against the heir presumptive, Charles II August, Duke of Zweibrücken, everyone opponents to the territorial exchange.
2. The threat of Catherine of Russia to intervene on the side of Prussia with 50,000 Russian troops forced King Louis XVI of France to reconsider his position, despite that Vergennes has considered the Austrians untrustworthy and he had not approved of the shift of France's traditional bonds (result of The Diplomatic Revolution of 1756).
IF France did not give his support to the rebellious British colonies in North America, would have had in its interest a continental engagement and the interest in maintaining its influence among the German states, would have secured to Joseph their military support for a war against Prussia.
Meanwhile, Britain, Prussia's strongest ally, was already mired in a war in North America.