Thank you for your response. I'm clear about the limitation of Fuji G mount and also agree on the jargons, however until there is more universally adopted terms, "full/crop" still a convenient and understood way to talking about them.
I know it is quixotic (after all, we still measure engine power output by comparison to horses!) but in a forum like this full of knowledgable photographers, using sizes in mm seems easy, accurate, informative, and free of misleading connotations: 36x24, 44x33, 52x40, etc.
After all that is how large film formats and prints have always been described (but with inches): 4x5, 5x7, 8x10 and so on. Also, is some countries, "36x24" is a common usage for the standard 35mm film formats clearly photographers can handle it. (And those numerical descriptions are shorter than "full frame" or "crop format", so there can be no complaint on that count.)
Anyway, I have "corrected" your subject line!
And yes, I do mean mirrorless with EVF. Would you care to elaborate why you think there's little chance to seeing them with 56x40mm sensor?
Other have made some good arguments, so I do not have much to add. However, Eric's point about the coming 100MP sensor in 44x33mm format does make me think that there is a very small and shrinking range of application where the larger 52x40mm format would show any significant advantage, because the vast majority of scenes cannot sustain even as much detail as a 100MP sensor gives.
Why? In short, due to the trade-off between limiting OOF blurring (requiring a small enough aperture size) and limiting diffraction blurring (requiring a larger enough aperture size), which sets the same limit on total image detail regardless of format. If anything, seeking higher resolution to make use of higher pixel counts requires ever smaller apertures to get the desired main scene elements "in focus" to a tighter standard, and then diffraction effects get worse.
Also, stitching is often a far less expensive alternative with stationary subjects.