Max, I really like the blue/grey color scheme. Definitely my favorite of these two. But is seems a little "modern" to me, just out of the shipyard condition. Some "modern" freighters or passenger ships could really benefit from this color combination.
I really believe that the plain grey, gives the merchants a more "weathered", sea-beaten, more authentic look. I also agree with your comment about war shortages.
I know, I didn't help much with my post... I like them both.
Billy.