As someone that bought into RF specifically due to the excellent optics in RF lenses especially relative to their reduced size and weight, I'm not interested in purchasing EF lenses, which are larger and heavier than they need to be, if they were native to the RF mount. Let's see those compact high performing primes that Canon is clearly capable of making. I'm hoping Canon launches the RF 35L, though at f/1.2 it'll probably be as big as the EF 1.4L II which is already pretty huge for 35mm (relative to 35mm's usefulness as a versatile walkaround lens for travel, kids, street). Here's hoping it's meaningfully smaller and lighter, and ideally cheaper (good joke).
In theory, mirrorless lenses are only shorter than SLR lenses under 40mm focal length. On an SLR, this is because optical and engineering effort has to be included in the optical formula to account for the physical distance that the mirror box occupies. Most SLR lenses under 40mm are a retro focus design. which is larger and more complex and the focal length could be on a mirrorless format. One an RF lens, there is no mirror box to account for. However, we are seeing on most RF lenses a funky (and expensive) array of Aspherical last element groups to bend the light rays from the rear element to the sensor. Also modern lenses are used a lot of videography and require more exotic and complicated focus motor systems than thier older "photo only" brethren. All of the EF lenses have an focus system that rotates (internally) the focus groups. All of the RF lenses have their focus groups sliding back and forth on rails. Photographer's don't care for this, but videographers do.
In theory, tele focus lenses will all be longer and slightly heavier on RF than EF, but the wide angle lenses should be superior, smaller and lighter. If you look at say the EF 400mm f2.8 L IS III, on the RF mount (it's the same lens, just adapted) it's heavier and longer to account for the baked in adapter. A ground up RF version redesign wouldn't be smaller or lighter unless Canon can utilise some other funky wizardry / technology.
Some lenses have been made smaller (like the amazing RF 70-200mm f2.8 L IS) because they have cunningly change the optical design so that it retracts at the wide end and extends at the long end. Rack the lens back to 70mm and it looks tiny compared to the EF version. However at 200mm..it's pretty much the same size.
The both the EF 24mm f1.4 II L and EF 35mm f1.4 II L are fine lenses. I have no idea how Canon can improve upon them in terms of a worthy / worth while upgrade other than open up the Aperture by 1/3rd of a stop, increase the AF speed and accuracy a touch and add and Image Stabiliser. The latter isn't particularly important considering the angle of view and it's relation to a low shutter speed.
I use a mk 1 EF 35mm f1.4 L, it's a lens that I bought new over 12 years ago and it's been amazing and I've loved the imagery that I've created with it it. It's truly an "Art portraiture" lens. it's hard to upgrade it to a MkII when the mkI is still turning in great images. However...come the arrival of the long awaited RF version...there will be a flood of S/H EF 35mm L II's on the used market and I might well snap one up then.