I have little troubles winning as Union, with their superior troop & weapons quality. As Confederates however, I have troubles even with emulating their successful tactics on 1st day of battle.
I did my homework, I think, and already looked at various tips for playing as CSA but they just don't seem to work. I hear about how CSA have superior morale, suited for offensive tactics and charges. The reality in game is that CSA "cannon fodder" brigades like Davis lose morale almost immediately after reaching enemy line, when they have superior numbers (vs Cutler) and are not fired upon. Then they fall back in disarray and suffer great losses. Sure, one could say that Cutler is good even for 2-star brigade and requires adequate 3-star Confederate brigade to bring them down, but then where's that superior morale I hear so much about? It's all troop quality that seems to matter, and CSA doesn't have much to offer here. There are not enough men in 3-stars CSA brigade to defeat all 2-star USA brigades.
Also, much of success on 1st day has been attributed to CSA's numerical advantage that doesn't seem that great in game. Pettigrew brigade may have 2,500 men but they're basically good for nothing, I doubt they could survive the clash with Buford's cavalry the day before battle, as they did in real life.
The only time I was rather successful was when, with all my brigades, I marched from McPherson's ridge. In what looked like an AI bug (Opportunist), Union forces have all retreated behind Seminary ridge, allowing me to take it along with Seminary itself almost with no shots fired, resulting in epic victory. I didn't manage to repeat that anytime again.
I realize that there are many successful attempts at what I'm trying to do, so any advice on what I'm doing wrong would be appreciated.