Interesting. Same problem here.
We have a guild made by 16 people, but only 3-4 are active. Other players stop playing, I guess.
Definitely the first thing to fix is the chat. It's impossible to communicate this way. And if I send a private messa to somebody, it would be nice, if the receiver gets a notification in the phone, so he can open the game and answer.
If I'd like to contact somebody that was active in last days and then disappeared...I have no way, if he doesn't open the game.
And chat typing should improved too.....anyway the notification to me is more important.