Nice concept!
We had a hard time with knowing when our messages were sent and when they weren't. Sometimes it would show a message I sent, leading me to believe it got there, but it did not. Or vice versa. (My wife and I played in the same room, and then compared notes after.) Was that intentional?
I found that I could resend or reformulate ideas that didn't come through, but without knowing when they did or didn't come through, that was really way too tough.