One thing one needs to understand about Canon is that they always determine the market of what the camera (camcorder) is for.
Examples: the RF lenses are made for high resolution, so there will be the camera like that at some point, more than 50 megapixels.
But that camera will be way worse for video than this EOS R. It will be much more like a stills camera. That will be the one without AA filter, but not the rest, because it causes problems for video, especially for higher framerates.
Then can also do a cheaper, lighter, more entry level camera with less features, inferior LCD, EVF, possibly a 6D II sensor or maybe something newer. But maybe it couldn't be priced that much cheaper, while also being able to regain the development costs, and they won't do it for now.
Or they can do like an XC-like video-focused 'compact camcorder' camera with a video-oriented sensor.
That will be way worse for stills, might have EF mount, a fixed built-in ND and no mechanical shutter and priced quite high.
For now, the EOS R with the adapter kind of fits this bill as well.
Or they just might do a C100 Mark III instead of that, sort of like an A-cam for the EOS R, much more video-oriented sensor with less rolling shutter, etc. but bringing its video specs (like EVF, LCD, DPAF area, codec) at least up to EOS R level (so no raw, but better 10-bit external output compared to the C200). Depends on where they could price this.
Of course they are going to do a more 'Pro' oriented camera, based on the difference between the 5D IV and 1DX II it will cost quite a bit more.
And they could give it great video, since it is there in the sensor already and even give it C-Log. But that camera, with those features (with added 'refreshments', like 10-bit 4:2:2 external 4k60p) would actually start to hurt their Cinema line. So they won't do it even for more considerably more than the EOS R, the improvements will focus on stills performance.
I don't think they will bring up the concept of a separate C model again like with the 1DC (the most depreciated camera, ever)
Image stabilisation is probably reserved for the next generation of cameras, before this is expanded with these models, unless they come out very slowly.
Maybe the Cinema EOS Line reaches new and unseen heights, and then they can start bringing the rest up to a certain point as well.
Now, they have gotten themselves a ridiculous number of things to choose from. (A bit like cooking, with many great ingredients)
But since the 50D and 5D Mark III, it became quite clear, that they will pretty much Never make a camera, that is unlimited at everything (unless they could make more profit on it with not limiting it, which is almost always not the case, since they prefer the user to have more cameras/camcorders, as many as possible)
