Lets assume, that traditional "Old Jogaila" theory is true (so he really was born around 1352 rather than 8-10 years later) AND that before Hedwig d'Anjou is available he is already married (perhaps with Rurikid princess ) and has a son (<insert random Lithuanian name> @Augenis )
Now lets go to details: Jogaila's son is born during early 1370s, raised in father's faith, has no siblings and his mother lives at least until mid 1380s. Meanwhile in Poland situation after death of Louis d'Anjou looks like in OTL. Diffetence is, that Jogaila is not available for Hedwig, but... his son is.
So instead of instant union of two realms, it is possible, that Jogaila sends his son (after they both agree to convert to Catholicism) to Cracow to marry Hedwig? Thus Grand Duke of Lithuania and King of Poland are not the same person, but father and son? So Jogaila still resides in Vilnius and can rule GDL personally without need to appoint Skirgaila as his governor (which in turn triggered Vytautas' reaction). Something, that should make GDL more stable. What would be conditions of ATL Union of Krewo? Certainly no incorporation as long as Jogaila lives.
Now lets go to details: Jogaila's son is born during early 1370s, raised in father's faith, has no siblings and his mother lives at least until mid 1380s. Meanwhile in Poland situation after death of Louis d'Anjou looks like in OTL. Diffetence is, that Jogaila is not available for Hedwig, but... his son is.
So instead of instant union of two realms, it is possible, that Jogaila sends his son (after they both agree to convert to Catholicism) to Cracow to marry Hedwig? Thus Grand Duke of Lithuania and King of Poland are not the same person, but father and son? So Jogaila still resides in Vilnius and can rule GDL personally without need to appoint Skirgaila as his governor (which in turn triggered Vytautas' reaction). Something, that should make GDL more stable. What would be conditions of ATL Union of Krewo? Certainly no incorporation as long as Jogaila lives.