The link shows several things, but the big one is the distortion that the 14L2 displays. It's CA is a bit harsh too.
Whatever your choice, it's a lot of moolah. So - assuming you still want to play, you might consider the TS-E 17/4L. It can be used to provide coverage equivalent to 11.8 mm (in pano mode as a 52x24 frame) or about 12.3 mm (when you make up a 4-exposure 50x32 image and 12.8 mm when used to simulate a 48x36 MF frame.)
Beside the versatility of the tilt and shift, the lens also accepts a 1.4x tc and is difficult to distinguish from the 24/3.5L (except that the field curvature is different.)
Fwiw, this is exactly why I don't own a ZE 15/2.8... I use a tripod for landscapes and architecture.