Give us a difficulty/mode setting that forces us to play stealthy. The mission resets automatically if you trigger a full alert. Obviously some missions you have to, but I think this would be great for most of them.
I just have friends that mess up and trigger alarms. There's no way just simply restart a mission if it gets out of hand. This would be a way to force people in your lobby to play stealthily, and if something goes wrong, you wouldn't have to wipe the team to restart.