I think the 1200mm F/8L lens will be a lens that gets made and doesn't change for a very long time. For Canon it's probably important to have it in their RF lens line-up, but I don't think it will rocket off the shelves when you can throw a 2x on a 600mm and get the same result, alongside having the shorter, brighter option of 600 F/4. But for Canon they only need to make that lens design on the RF mount once in 10-15 years, like the 800mm F/5.6 which didn't get updated nearly as much as the 600mm F/4L IS. I could very well imagine a RF 600mm F/4L IS mark III before a 1200mm F/8L IS II. Basically, I think Canon wants to make their baseline line-up so that people have all these options 15 years from now.
As for autofocus tilt-shift, I think those lenses will be huge for the people who need them, or the people who don't realize yet that they need them. I always felt limited using the tilt-shifts at my job, as manual focus isn't particularly easy in fast pace environments when you're an event/news photographer. These could be sweet for the wedding photogs I know as well that use tilt-shifts almost every wedding, though I think the longer end would be more applicable to them. Landscape/architecture photographers probably won't feel pressed to get them, though high-end architecture photographers probably have the budget to justify it, considering how expensive the manual-focus ones were already.
Someone brought up the age-old "why are they making such big lenses for mirrorless" and I think one thing that has been apparent is that Canon considers the standard of acceptable weight/size to be DSLR size and weight. The RF 50mm F/1.2 is about the size of a EF 50 F/1.2 + RF-EF adapter, the RF 28-70 is about the length of the EF 24-70 F/2.8 + EF-RF adapter, and so forth. I think the way Canon sees all of this as is, if a professional was already willing to fill their bag with the big size of DSLRS and their glass, they can push the limits of lens design to make way more impressive lenses that still fit in the same general weight/size of their DSLR counterparts. They're not wrong, either, I doubt I would have considered the RF 28-70 F/2 if it was on EF, but I don't mind the extra size/weight when the combination of it and the R5 is lighter/smaller than the 1DX2 + EF 24-70. For those who want compact size, they've definitely made lenses for you like the RF 70-200, 35, 50 F/1.8, etc.
The most interesting lenses to me in my uses are the RF 14-35 F/4, 24mm F/1.8, and 400mm F/2.8. I really have come close to getting a 300mm F/2.8L IS II several times this year, but I'd rather get an RF mount option, and I feel like 300mm f/2.8 is too short for my uses, I can easily crop 200mm f/2.8 from the R5 to 300mm and be mostly fine with the results. I think if I get a supertelephoto, it's going to be the RF 400mm f/2.8 at some point, though probably not on release.
The RF 14-35mm F/4 sounds like a perfect replacement for my 16-35mm F/4L IS, but I'll just be hoping it takes 82mm filters so I can use it on my Lee filter system still, we'll see what happens in the lead-up to more specs being announced, I've already come close to getting the RF 15-35 F/2.8L IS a few times.
And then finally the RF 24mm F/1.8 STM sounds like an instant pre-order. That would be the perfect wide lens to throw in my belt-kit, and would make the perfect partner to the RF 28-70 F/2 to ensure I always still have the 24mm option if I need it.