I think putting a Clan War Chat is a good idea, it is also a way for the opposing clans to communicate.
If you think it's prone to trash talking, I think it doesn't matter since I don't think clans will face each other several times. It can also enhance the war's excitement and it will also make the clans wanting to win more.
I hope you consider this a good idea and adopt it to your game. Clash ON!
