The size of the new 1815 is: 40 x 8,9 mm
Yes, it is a big step, but don´t forget about the new/bigger movement. To me it looks quite good (from the pictures).
RL is 40,5 x 10,6 mm, Lange 1 is 38,5 mm and a bit higher, ....
Most Lange´s are well balanced.
And know we need wristshots from FX, Nicholas, ... 
Oliver