The RF 28mm f/2.8 is good, but I'm not bringing it out for low light situations, and I'm not very fond of pancake lenses. The lens vignettes heavily at f/2.8, an aperture that would be stopping down with most prime lenses, but it is not with this one.
I'm mostly okay with software corrections, that's not my point, but I'd prefer having that level of vignette at f/1.8 or wider, and being able to stop down to f/2.8 for a cleaner image, like many lenses allow us to.
A regular 28mm, with a proper lens hood, would do. I wouldn't necessarily want f/1.4, I'd be glad with a RF 28mm f/1.8 STM, but the 45mm is setting a precedent for extremely wide apertures, so I guess one can dream. Also, it could make an amazing standard lens for APS-C users, since a RF-S 32mm f/1.4 is nowhere to be found, so I think there may be a market for a budget, but fast, 28mm, specially with a price and form factor similar to that of the 45.
As for a L-series 28mm...yeah, at this point, I doubt it.
