It isn't focal length that is the primary concern with much architectural work, it is angle of view. A µ4/3 lens must have half the focal length of a FF lens to give the same angle of view.
There is a simplicity of lens design advantage to µ4/3 for focal lengths between the typical 42-46mm registration distances of SLRs and the 19.25mm registration distance of µ4/3 cameras. But that is mostly offset by the need for focal lengths half as long to give the same angle of view.
When talking about much wider angles of view than can be had by a 20mm µ4/3 lens or a 40mm FF lens both µ4/3 and APS-C or FF cameras must use lenses with a retrofocus design. This eventually gives the advantage in terms of ease and simplicity of design and complexity of manufacturing back to the larger format, although at an increased cost of size and weight.
There's also the issue of low light performance when talking about smaller formats. To get angle of view and exposure equivalency of a 17mm f/4 FF lens one would need an 8.5mm f/4 lens. Even then, the lower efficiency of smaller sensors would make the images from such a camera noisier. Since a lot of architectural work is done in low light, this tends to be problematic for such work.
Beyond that, the need to do perspective control gives the greatest advantage to the larger formats that have bellows type cameras with full movements. The Tilt-Shift or Perspective Control lenses used on 35mm format cameras are a bit of a compromise, in terms of both range of movements and the types of movements that can be simultaneously combined, compared to a LF or MF view camera. The T/S adapters for use with µ4/3 lenses are an even greater compromise, both in terms of the movements they provide and the optical image quality they allow. To use such an adapter one must also use a lens that projects a larger image circle than that projected by a typical µ4/3 lens.
So now one needs a shorter focal length lens to obtain a wide enough angle of view while also needing a lens with a wider image circle to allow for movements that move away the optical center of the lens away from the center of the sensor and project an image oval instead of an image circle on the camera's sensor. So instead of needing a 8.5mm f/4 µ4/3 lens, we need an 8.5mm f/4 APS-C or FF lens to put in front of our T/S adapter!