I would say yes, it is a very good historical drama. Because it's about how one family get through the war, yeah, there are action scenes that add a lot of intensity and are important to the story. There are battle field scenes, explosions, guns, fires, fights, escapes, threatening situations and killing - more than once I reflected upon the madness of war and human nature... but this is definitely not just, or even mostly, an action drama. You get to follow one family and their loved ones, especially the twin brother and sister who are innocent and playful and just about to grow up when the drama begins. There is also some romance. The characters all felt very real and likable to me (even though I didn't like all of them in the beginning) and that's what made this drama a perfect mix of heartwarming and heartbreaking. I didn't want it to end... but I still felt happy when I watched the last episode. The way you do when you watch a very good one! To me The Battle of Changsha was very near perfection. I rated it 9.5.
You should also watch the c-drama The Disguiser. It also has very strong characters and lots of family moments but with more focus on actually fighting the war and you get to see the different sides and lots of plotting and fighting. Not like fighting on the battle field but spying on and killing the enemy. I rated it 8.5.