Yeah, they could do a better job of letting everyone know. They usually post something on twitter, and I think if you're playing they give you a heads up message on your console. The weekly updates usually say the date of the next patch, but no specific time. Ideally, yes you'd think they do this stuff when the least amount of players are on. All in all, it's usually only a few hours that we have to wait. I'm excited to see the new Iron Banner gear.