Good Grief! Some of it sounds like crap! As in throw in everything but the kitchen sink crap. I hope it doesn't read that way. Will try and reserve judgement, but still...
It read well enough. The plot device used was believable, Imho, it is just that Battle Ground is just that. The entire book is Chitchen Itza, which we are not used to so it takes a bit of adjustment. If you aren't fresh off of Peace Talks it may not read as well, and I wouldn't recommend ever reading Battle Ground alone/without Peace Talks.
This book was another Changes, it cleared the field of a bunch of issues, to set up the next goal post. I can tell that however many books are left, Jim has started to summon Godzilla, and the waters are starting to churn.
What interests me mostly is how he left things between Harry and the White Council. It suggests that in the next book or book after the White Council will be hit imo, as the events here have thoroughly fermented the situation for dissolution, abandonement, and open internal strife.
Edit:
I will also be interested to see what happens with the Grey Council now...especially since Harry is even more isolated than before.