I doubt they'll make a 28mm VCM. At this point, I'm just hoping for "f/2 or faster".
The EF mount had both f/1.8 and f/2.8 28mm lenses, so there's precedent.
As for ~40mm, in my opinion that is covered now by the RF 45, which gets us 1mm closer to 43 than a 40, so it's even better.