I wonder whether there's been some kind of legal/copyright reason for the wave of logo changes in the relatively-recent past. Remember that Marvel (slightly) changed theirs, as seen on the more recent Omniboo; DC's odd new logo has now begun appearing on spines, and as noted Dark Horse have tweaked their dark horse on spines now, too.

Is it really just a giant coincidence? Or is it slightly-a-coincidence and all three are trying for "brand cohesion" now that the most important market is iPad application logos that may have needed tweaking from the company-standard ones?