It's not bad for a movie to be lengthy, but this nearly 4 hrs. long Civil War epic is guilty of many cinematic crimes besides, the most egregious of which is that it is mercilessly boring. Maybe for some Civil War buffs it would be of more value, but I bet that for even them, it would only be so for the battle reenactments. Often, stiff and emotionless acting is referred to as "wooden", and that term could be applied to this film as a whole. The American Civil War is rendered into this epic conflict that was fought for no reason at all really. Slavery is mentioned a few times and declared to be bad, but it's not shown as being very much related to the war at all. In fact, there is no clear explanation for the war. The South secedes because it's damn well their right to, and the North invades their own country because their tyrannical or misguided or whatever, even though the South only believes they're the same country as the North when the script deems it convenient.
The filmmakers are obviously Civil War obsessed, but the only benefit to that is the play-by-play battle recreations, but that doesn't count for much if they're filmed so clinically and sanitized that they become mere textbook portrayals. The generals and officers are so very idolized here that they bare no interest at all as they mechanically spout such reverential and sober monologues of tremendous self-importance, not unlike the overall approach to the material by the filmmakers.