It is my opinion that the riser is canted like this
/ to match the natural angle of your arm (for a right handed shooter, \\ for LH). The limbs will actually be more vertical than a "standard" design with your hand in it's natural angle.
Let's say that these two lines are 2 bows. The bow on the left has an offset or canted riser and the one on the right is of conventional design.
The riser section of both bows are nearly the same angle (as close as I could draw) but you see the bow on the left has it's limbs more vertical.
I might be all wrong about this, but this is how I see the Wolfer design.