Hollywood is good at entertainment, but they are not good historians most of the time.Movies, aside from documentaries, are made for profit, to appeal to a mass audience that can bring in dollars, so there is little incentive to be historically accurate.
The two movies you mentioned grasshopper were pretty much from the Mexican perspective of the War. I think a good drama with the American view would be interesting also. There were some very interresting characters to draw from, including General Winfield Scott, and future Civil War Generals Robert E Lee, Ulysses S. Grant, and Stonewall Jackson.The battle had been a significant victory for the US. The efforts of the U S Marines in this battle and subsequent occupation of Mexico City are memorialized by the opening lines of the Marine Hymm, From the halls of Montezuma...so at least we would have a musical score for a movie