Yea, 45 degrees is one heck of a list for sure. I remember, during my early flying days, finding out that in a 45 degree bank, while maintaining a constant altitude, in a coordinated turn the load was 2 Gs. In other words, if you were sitting on a scale when doing that it would register twice your weight. Of course a ship going into a turn with a 45 degree list is going to be anything but coordinated, and more than likely a list like that is probably due to stuff that might make the ship ready for sinking.
It is my understanding that it isn't so much the degree of list that concerns marine surveyors but the ability for a vessel to rapidly recover. Back when I was playing around with commercial fishing I enrolled in a number of courses dealing with seafaring, if I recall correctly, the deeper the draft of the vessel the better and faster the ability to recover from a severe roll.
We were on the old Royal Princess more than once, one time when the new Grand Princess was still in the shipyard the captain of the Royal was explaining to me how the new Grand, at 2.5 times the gross tonnage of the Royal, would have the same draft and be able to negotiate the same shallow ports like the one we were in at that time, Venice, (incidentally that captain went on to be the first captain of the Grand Princess).
Anyway, that has held true with all these new huge ships, they have a very shallow draft in relation to their bulk, in other words, relatively flat bottoms. Now, it is my understanding and experience to believe these huge ships have had rare opportunities to be tested in super high seas due all the safeguards today in operations and weather reporting necessary to protect guests from danger and unpleasant sailing. Hey, we can attest to that, almost all our voyages have been on calm seas even though we have had to circumnavigate big blows. So what happens when one of these giant ships gets really tested? Perhaps the design of the Anthem of the Seas might be telling us all something.