I don't really think that Drysc has to justify downtime (seeing as it on Tuesday mornings for most players, not to mention that with all the changes we've seen come down lately, downtime has definitely been justified), but he does it anyway over on the forums. He's right-- things used to be a lot worse (I can definitely remember having a secondary realm to escape to when my main realm was down), and with the two week cycle Blizzard has going on right now, actual downtime is few and far between. Sure, it means that every Tuesday morning you've got to go for a walk rather than play the game, but that's definitely not a bad problem to have.
Sure, if Tuesday morning is a time you usually play, it's not that much fun (I remember I always used to have Tuesday mornings off when I worked retail, and every week I forgot, and tried to sign on before realizing the realms were down). But until Blizzard figures out how to update the game while it stays live, the situation we've got now ends up being a pretty good solution.