I like this feature.
However, I would like there to be a way for people to flag themselves as non-participants. I want to be able to attack people that I know want to be attacked. As it stands now, all I can do is check through the players "Favorite Attack" and "Strongest Attack" and then guess if they want to participate or not. It does feel a little like I'm being a bully if I just go out and squish players that don't want to be in on the war.
Also, I play on my phone and I have a real hard time understanding what some of the images are that are required components for each attack. Making them larger or just having the ability to mouse over the graphic and make it larger would help.
Finally, I also wish there was a way to see what my attacks need from the main screen. Going back and forth between the war map then the regular map just to compare what I need to what is coming up is a bit of a pain.