What nations you add to the Age of Empires 4?
Will the Poles finally see Poland in Age of Empires 4?
A lot of modifications and DLC appeared for Age of Empires 2. Today there is only Slavic nation which is more similar to Russian than Polish.
Please read about Poland in Middle Ages and you will find out that it could be playable nation.
Poland was one of the sides in the Battle of Grunwald, which was one of the greatest battle in Middle Ages. In Battle of Grunwald fought about 66 thoundsands people (on both sides) and Poland won with the Teuthonic Knights.
It would be fantastic if we could see polish winged hussars in new Age of Empires, but it depends when you (developers) want to finish history in game (in what date). Because Polish winged hussars appeared in beginning of XVI century.