This galley arrangement is not all that unusual in the 747, several airlines, including KLM as mentioned above, use it (or different varaiations on the theme, I think some QF
747s had an "L" shaped galley) and the flight attendants, according to rumor, like it. The large galley provides a good amount of space to work in, which is important on long-haul flights where F and J class meals can be a bit complicated, its easy to set up carts for serving in the larger galley, provides lots of storage, and I guess is also a good place for F/A s to hang out (hide) during long flights. This arrangement does not take up very much more space, since the galley between cabin 2 and 3 on the 747 (which ususally serves J class and sometimes a portion of Y class) can be reduced in size.
The passenger cabin "on the other side of the galley" works better than it looks - on KLM flights its one of the quietest places on the aircraft with little aisle traffic and due to its reduced width, it somehow "feels like" the upper deck on the 747. Being next to the wall is not a big deal, on most very long haul flights, part of the flight is at night and during the day, passengers close the shades to get a look at the IFE.
Interesting note, on some flights, where there are not many J class passengers and Y is full or oversold, KLM will use this cabin for Y class passengers.....they attempt to put Economy Class Frequent Flyers into this cabin (I have lucked out a couple of times) but some passengers are just assigned into these seats by luck.