Chances of a fast wide prime?

Great Bustard wrote:

12mm f/2 on mFT is equivalent to 24mm f/4 on FF, where "equivalent to" means:

• The photos all have the same AOV (diagonal angle of view) and aperture (entrance pupil) diameter: 12mm / 2 = 24mm / 4 = 6mm.

• The photos all have the same DOF (as well as diffraction softening) when they have same perspective (subject-camera distance), AOV, aperture diameter, and display size.

• The photos all have the same motion blur and the same total amount of light falls on the sensor when the aperture diameter and shutter speed are the same (e.g. ISO 100 on mFT and ISO 400 on FF).

• The photos all have the same same noise when the same total amount of light falls on the sensor if the sensors are equally efficient (less noise if the sensor is more efficient, more noise if the sensor is less efficient).

• Other elements of IQ, such as resolution, bokeh, flare resistance, etc., as well as elements of operation, such as AF speed/accuracy, size, weight, etc., are not covered in this use of the term "equivalent".