In an ideal world, the artist has to a) understand the book and b) create a cover that sums it up and c) produce an alternative version that isn't too heavy for the e-book.
The difference between e-book requirements and print are huge, and a few of the recent Penguin e-books I've bought all have the same cover (the Penguin logo) which looks to me like the editors just punted on the issue.
So I applaud this effort. The problem they are solving is much more difficult than it looks from the outside, and they are doing an impressive job even though the results may look less than ideal to some. Things like Project Gutenberg would be considerably enhanced if they had decent covers, and any scheme for auto-generating them that isn't positively awful [] would really help.
[] I've gotta say the first purely geometric covers in the article aren't quite my cup of tea.