I'm a life long student of the era. Been to Gettysburg over 3 dozen times and spend an average of 5 nights in town. Six of my ancestors were there in various Georgia regiments. I've walked the ground where they walked, studied the terrain, read every first hand account of the battle that I can find, paid licensed battlefield guides to give me tours specifc to the regiments my ancestors served in, etc.. No, I'm not an expert, but I know a heck of a lot about the Gettysburg Campaign.
I'm a SP user and play a LOT. Rarely ever play single, random scenarios, but rather full campaigns. Usually as CSA because it's harder to win. Not because the game is unbalanced, but because in the actual campaign, the CSA was outmanned, out supplied, out of reliable info from their cavalry and probably most important of all, the Union had the "good ground". The terrain played a huge part in the outcome. Of course, this is all my opinion.
I can win against the Union but only once was it an Epic Victory and that was several updates ago. Marginal victory is about as good as I can do now. As the union, I can get that Epic win. Again, though, never once has it occurred to me that the reason for that is because the game play is unbalanced.
I love the game!