I totally agree with all that you said and you beat me to it! After giving it a test last night, I found that Sony probably should have put some sort of locking mechanism so the wedge doesn't swing toward you when you're lying in bed. When it does fall, it has a swinging door feel to it. You definitely have to keep your thumb on the spine to hold the wedge in place. I'm actually thinking I could do with some sort of band to keep it place... not sure, it might give it a ghetto look to it or cover too much of the screen. Will have to play around with it.
Another thing I noticed is that the distribution of the light is choppy on the left side and it evens out nicely on the right half of the screen. Kiss your beautiful screen goodbye when you use this at night in the dark. When using the light, the screen, looks has a photocopied page look to it. The best way I can describe it is take a dead-tree book, open it to the middle and take a photocopy of a page. You'll notice that the part of the page closest to the spine tends to be darker. That is exactly how the reader looks when using the wedge case. Look at the picture I took in a previous post.
Dust. The wedge really highlights any dust that is on the wedge light. Dust shows up as little bright dots... which is somewhat annoying. Just make sure things are clean. It also doesn't help things any that mine came with a little scratch
I'm going to give it another couple of days and see if I get used to it. If not, I'll be taking it back to the Sony store.