I've had the opportunity to fly the 747-8 already twice in economy and there are several extremely disappointing features in how LH has handled the interior design and layout.
First of all, the Toilet layout and size in Y class is a pure and utter disaster. It is strange to see a product that has been developed 20 years after the 777 (superb machine) with so many flaws. The toilets are small. I mean S M A L L. I am not a big person, but i can barely move in them, compared to the LH A340-600 or the 777 or even the normal 320/330/340/380 family the designers had a problem...a bad night, bad education, no inspiration or a really bad brief from LH.
It is so bad that I will avoid flying the 747-8 in Y in the future!
Beware if you have little children. The diaper changing table is a joke, laugh or insult!
The size of it is ridiculous and was clearly designed by somebody who never handled a baby in their life. There is also not enough toilets for so many passengers. Overall, a major design disaster.
What was the LH/BOEING team thinking I do not know. Clearly they did not have passenger comfort, privacy and all that goes in the "care for your customers" corner in mind. Maybe they wanted to put in two more rows of seats, who knows. But they failed miserably.