I think this list is the best thing ever.
As a Pole, I'd like to review your choice of Polish leaders
There is one extremely important person missing from the list.
Tadeusz Kosciuszko. He is insanely popular Polish national hero and highest leader of last desperate attempts to save the nation from partitions. He is so popular and important I'm pretty sure he'd be in every kind of list of "most popular Polish people of history" and near top of "most popular Polish leaders of history" rankings. He is the kind of leader who would not generate even the smallest controversy when added to the game, everyone would nod "yep, Kosciuszko, cool choice". There are even minorities of people who criticize Chrobry, Casimir, Sobieski and Pilsudski for various controversial aspects - Kosciuszko is pure.
Otherwise, no major Polish leaders are missing. There are however several that shouldn't be even allowed to come near "potential leaders" lists.
Stanislaw August Poniatowski - the most controversial figure of entire Polish history, with overall opinion of historians and public tending to be negative. He was a sort of submissive lover of Catherine the Great which is already pathetic, ineffectual, unpopular, and ultimately failed to protect the country after doing many questionable acts. Pls no.
Augustus II and Mieszko II are considered one of the worst Polish kings ever lol, the second one almost led to complete annihilation of Poland and first one would be considered borderline insulting to appear in civ
Henry the Pious was one of many feudal princes of divided Poland who is obscure in every regard except his utter defeat (and death) versus Mongols.
Boleslaw II is another very controversial figure for the court conflict that caused him to torture and kill the bishop (now considered saint) and as a result being kicked out of his own throne and country by public backslash lol.