I agree about the illustrations but they really were a necessary evil. Jackson already said he didn't want any reenactments and since there's no footage of actual battles, that's all he had to depict them as accurately possible given what was available at the time of the war. Otherwise you'd be looking at ten minutes of nothing but pictures and footage of corpses.
I think you could have skipped the "battle" scene entirely, honestly. In the postscript, Jackson mentioned all of the other footage and topics they had to excise, and I was immediately disappointed in that choice.