I think this is most likely to do with the actual specifications of the cameras - the 1.3x crop boggles the mind a bit and the increasing quality of 1.6 crop bodies are encroaching on that space for wildlife shooters a bit. They certainly could do a bit to overhaul that end. I'm not sure that there needs to be more differentiation in the upper and middle ranges, just get something out there to really replace their last EOS-1D full frame mark, and improve (but not further differentiate) the middle range with the full-frame 5D replacement (maybe a 1.3x crop would be tolerated there; I don't know). I don't think the actual names of the cameras are going to change, other than to perhaps squish a few of the most egregious naming conventions (i.e. adding -s); if you care to find out why:
Having two 1D bodies makes some sense in that they want to remain the go-to choice for professionals - if they will clearly represent differences in the best use of each camera (portrait / landscape vs. sports, or EV/dynamic range vs. sheer ISO, seems to be the usual balancing act). It doesn't make sense to me that they might remove the 1D line; it has always represented their "#1" camera, even before there was a 1D there was a EOS 1. If they do wipe out the moniker, they will doubtless still have a top tier of cameras with some designation that is similar in its meaning. And if they wipe out the moniker 1D, then some real shakeup of the EF system is probably afoot, and I think video alone doesn't explain this (not sure of a EF system suited more to video - more on that in a moment - or an EF system with view camera type movements, which again wouldn't be well suited to the current group of EF lenses). It would make even less sense (if this was suggested) to keep the 1Ds and drop the plain 1D.
Splitting the 5D line for video and non-video especially is a proposition that seems to carry more cons than pros, since video is simply (protestations about what we don't know about internal Canon engineering aside) a firmware feature requiring minimal hardware support, and a good buzzword and value extender for marketing purposes.
An EF mount video system might make somewhat more sense...but Canon already has its camcorders, and now (against my earlier predictions) entries in the PL-mount category - systems that are perfectly suited for the two traditional opposed genres in motion pictures of flexibility (news, many television shows) and ultimate control (movies and large-budget features). There may be a slight argument to be made for professional DSLR video in certain circumstances, but it would be a small and specialist market.
If you theorize that you could split some camera lines, with some side having a sensor more suited to video (which seems possible to make), as the EF system stands it would still generally be a pretty woeful choice for professionals making video productions. An EF system may not be far behind some other digital video systems, and at a good price (assuming you aren't gearing up for a professional production in which case investing that money in traditional gear, even just one lens, is preferable), but the number of lenses in the system that retain constant focus and/or that do not change their angle of view when zooming is small, and smaller still are the number of these that have sufficiently large maximum apertures and have focus rings up to the standards of professional focus pulling. But hey, if Canon wants to refresh their whole line with f/2.8 parfocals with movie-quality focus rings, three cheers!
At this point, it seems most of this discussion is going into the realms of trying to get diminishing returns from a set paradigm, not unlike Nikon trying to futz autofocus support into a mount that also supports their earliest non-AI lenses. To get the features mentioned here, Canon may well need a totally new mount - though, again, the fact they have now invested in both mounts (their proprietary camcorder mount as well as PL) means that this seems unlikely. I already took a shot at guessing Canon was not going to go to an "open" standard like the PL Mount; they didn't misjudge that market (where the whole point is not to get locked into a single system) like I did. Butchering the EOS series for the sake of iffy video support would be, quite frankly, a bigger betrayal of the EOS / EF ethos than anything Ken R. has ever had cause to complain about.