The entire game should be set up as to follow history in a plausible way, barring any intervention of the player. Not every time of course, that would be boring, but most of the time it should. So, in the end, AI Poland should be declining, most of the time. I wouldn't mind seeing a powerful Poland dominating central Europe and beyond every once in while, but not every game. Not even every other or every third. Maybe, once in 10, 15 games.
This is not to say that Poland isn't important, but it's power for the better part of the time period was in decline. If devs give Poland such a starting position that even AI Poland could be dominant quite often, it kinda breaks the game for me. Yes we could argue that if X or Y didn't happen, then maybe someone would have done Z and Poland would have been much more powerful. Thing is, you could argue the same for about any state on the planet. Even better case than could be for the Ottomans, who were much greater threat and for a longer time than Poles, and again, I wouldn't want to see Ottomans controlling Paris very often.
This is not to say that Poland isn't important, but it's power for the better part of the time period was in decline. If devs give Poland such a starting position that even AI Poland could be dominant quite often, it kinda breaks the game for me. Yes we could argue that if X or Y didn't happen, then maybe someone would have done Z and Poland would have been much more powerful. Thing is, you could argue the same for about any state on the planet. Even better case than could be for the Ottomans, who were much greater threat and for a longer time than Poles, and again, I wouldn't want to see Ottomans controlling Paris very often.