I think this is one of those ideas that *sound* better than it actually is. In short, adding graphics and video to electronic book readers are the first couple of steps into losing what a 'book reader' should be.
Many argue that eReaders "just aren't the same" as a real, 3 dimensional book. I agree... both literally and figuratively, I suppose. However, educational text books are perfect for eReaders. They are often enormous, have to be frequently carried around in conjunction with others book and I'm pretty sure most people don't care about how a text book 'feels'. So moving eReaders to book = good idea.
However, with an LCD screen, this changes things a bit. First, I feel this is losing the focus of what an 'eReader' is. It hasn't lost it yet -- but it is getting there. It blurs the line between an eReader and a Tablet... which could be a little blurry with a laptop already.
Another drawback over eReaders as we know them is we're going to see a pretty intensive increase in power usage. This is now going to be a device that needs to be charged hourly, depending on the battery size and how much multimedia they plan on packing into this thing. Books don't have videos and while it is neat, again, it is losing focus of being an electronic book and falling into the realm of tablet.
Take it a couple of more steps with web browsing, a keyboard etc... It's not longer an eReader. Personally, I'd rather have a 'dual screen' laptop that I could types notes on and read at the same time, since I'm going to spend a lot of my time looking in the general direction of an LCD already.