So what was it about the last few thousand times this was brought up that wasn't 'proper'?
Since the artist's original description of the objection to the artwork was neither complete or accurate, his assessment of the reasons for the change are equally suspect.
Later in the blog he concedes that the original artwork was not an accurate representation of the game, which in and of itself is reason enough to change.
The only 'threat' I know of is one tiny site saying they didn't want to review the game if it meant displaying the original artwork. There may have been more, but I highly doubt there were any with more that 2 people involved in the site, or that had any significant traffic.
Every other aspect of the game was changed or influenced in some way based on feedback: story, quests, dialog, character design, world design, etc. Yet somehow cover art is sacred and is the only thing that must never, ever, ever be changed or it is censorship? Why is that, exactly?