YMMV.
By "the actual war" I didn't mean the fighting in and of itself. I meant the setting
of the fighting. The political horse-trading in Washington and elsewhere in the country as Lincoln and others try to manage the Republican Party and the war at the same time. The whole bizarre saga of the copperheads. The effects of the war on extant issues throughout the country such as Native American relations (Colorado, New Mexico, Utah) or the squabbling that became the Draft Riots. The economy at war. The foreign relations of the United States and Confederacy. The ideology of the war. And, of course, the interrelation between slavery, emancipation, and the course of the fighting.
You know: stuff that has to do more closely with the actual war than a
really long excursus through the 1830s, 1840s, and 1850s.
Now, obviously all of that stuff was related. A well-written history of the war has to take at least
some account of the history of slavery in the United States before the outbreak of fighting. But I felt that spending a full quarter of the book's text was overdoing it somewhat.
I too tended to skip McPherson's battle narratives, because they were either covering overly well-trod ground yet again and I was bored of them, or sometimes because I didn't feel as though they were that well written compared the segment on, say, "the counterrevolution of 1861".
Anyway, all this adds up to me feeling awfully ambiguous about the book and wishing to express that while others might well recommend it to others wishing to get into the subject - God knows I have in the past, sometimes on this very forum - I myself at this moment in time probably would not.