The issue is, there's a very LARGE system update that you have to go through (I think I read something like 5 gigs?). If you turn your system off during this mandatory update, like any mandatory update, your system bricks.
There's no way to know, but at the same time it probably isn't as bad as what you think. Why do I think that? Well, we're getting a disproportionately negative reaction simply because the vast majority of people whose consoles haven't bricked aren't coming here to say "Don't worry, I'm good".
Is it something to be concerned about? Well, if you think a power outage has a reasonable chance of happening, then yea. But chances are you'll be fine.