Wide angle zooms are a tricky subject. While the 16-35mm (ish) range is quite common and broadly useful, there's a lot of different niches and trade-offs, especially when you consider size/weight and cost...
The 8-15mm would be VERY interesting if it were rectilinear, though I would expect that to be very difficult to build... It's not listed anywhere near as wide as the fisheye, so maybe it is? The 11-24mm is 132mm long, so maybe this is a true ultra wide lens! I'd be on board. And 8-15mm would be a better trade off / compliment to the 14/15-35mm than the 11-24mm have been to the 16-35mm if they can reduce the size and weight.
wow, would I want that!
The 16-24mm does feel like a weird lens, but I guess I get it? If you could have a very light relatively affordable ($900) lens to compliment the 24-105 f4, maybe it makes sense?
Personally, I'm just now in the process of selling my RF15-35mm f2.8 for the RF 14-35mm, because I will really appreciate the smaller size walking around. And I've started going for my EF 8-15mm over the EF 11-24mm, too for similar reasons... though obviously they're very different beasts.