The Europeans seem to take a different approach to RV design, especially with respect to tongue weight. My guess is that it's probably due to the type of tow vehicle typically used.
I remember travelling in Holland a few years ago...and seeing quite a few trailers on the roads with similar forward-biased axle placement.
Most were about the size of an E15, pulled around by very small vehicles....something along the lines of a Ford Fiesta or Honda Fit.
It must be an interesting travel experience.