Video doesn't need as shallow DOF as stills.
You're right to say that video with shallow DOF isn't critically important for many people and is difficult to use - yet people still have been buying and using the HD video-enabled DSLRs and using them to replace production video cameras. Most people have been using the ability to replace camcorders - photojournalists shooting quick segments or making video notes, hobbyists using it as they would a camcorder (less than successfully I would add).
It is a new market but already we can see that it is split into two categories.
The real question about the evolution of video in the EOS format is whether they will try to make it more like a camcorder, to appeal to everybody (somewhat like the NEX I suppose) or whether they will try hard to make it more useful for pros. Professionals already love the low cost and maneuverability of DSLR video, and Canon probably would like the opportunity (or more accurately, recognizes they can't lose it, since these SLRs are going cheaper than even Canon's pro camcorders) to grab a new market and not rely on either their camcorders and even more expensive professional video equipment ($100,000 zooms for sports coverage aren't going to expand into new markets). From Canon's perspective, the troubling aspect is that this might gut pro video products, but since Canon just recently joined the PL mount group it seems that they didn't have much at stake in that market so far. Even if they don't cost as much per unit (remains to be seen) as a pro camcorder, they probably would be able to sell a good volume of them, and that could be more profitable. They are clearly gearing up to be able to move with the market with these moves, and perhaps not so confident that they can dictate how it will end up - which is just fine.
I previously have said that EF mount is pretty silly for video, as it stands with the current lens lineup (ignoring third party manual focus lenses, but not ignoring the problems with the video quality and usability of current DSLRs with video) but if they make some lenses appropriate for video, perhaps some even with autofocus capability - and all with good manual focus rings - this system will look more attractive to video users from both camps. They probably need continuous and quick video autofocus to get hobbyists on board, though - pros are already accustomed to manual focus for movie productions.
There are some quite interesting options possible if Canon goes into pro video - IS on video lenses has some obvious applications for even movie shooting, and should help free cinematographers from expensive rails and steadicam systems.
The one real hole in the system, so far, has been continuous focus. It's not much used for the movies but many people would buy a competitor's camera (say a Sony SLT) for just that reason.