Makes perfect sense. I don't understand why mass-market paperbacks don't use the same covers as hardcovers. I'm sure it wouldn't be difficult and the hardcovers are always better.
Sorry if I'm a bit behind (I'm just trying to catch up) but I also wanted to add that the reason they changed the covers was because the PB version was sent to all the grocery stores and junk, so they tried to appeal to that crowd (which, you must admit both version are similar to the rest of those novels). If you check the forums enough you'll find where EUOL (I think it was him) explained it in more detail.
However, I agree that if they want it to stand out, they should have left the HB covers.
As for all the comments about (as I call it) the ugly cover, check out the original discussions
here. As you can see, we all hated it from the beginning. I think I know the story behind why it was still used, but I don't want to say something and find out I'm wrong. (Also, if you look at the link that Sprig posted on the end, you'll see a VERY familiar image. I'm kind of glad it didn't become FE PB cover, but also glad it wasn't scrapped...
)