re: Nothing unusual about the slopes
The feature could be taken for an ordinary impact crater since it is "roundish".
However, take a look at this Hirise blow up of Victoria that shows this feature in better detail:
Opportunity Route Map.
http://www.unmannedspaceflight.com/index.php?act=Attach&type=post&id=10866
An ordinary impact crater should be round and bowl shaped. But this is more elliptical in shape and moreover appears filled in on the side closest to the edge of Victoria, rather than having a depression that is deepest in the center for a typical impact crater.
Also, this image makes clearer that any depression that appears is more like a linear gash off to the side as confirmed by the 3-d image made by the Opportunity rover.
Bob Clark