That's not entirely true. Ford began work on this revision of the Taurus/500 before the 500 came to market. However, I do see your point in as far as this: Ford has taken heavy criticisms over the 500's shortcomings, and it is apparent that Ford has gone to a lot of work to address these issues.
There is a lot of buzz going around about the new Taurus, a majority of it very positive. I think that while Ford is not out of the woods yet, they are taking the necessary steps to ensure their survival. I'm very interested to see what Ford does with the Taurus for the 6th generation.
To the topic at hand: I think they all look like very nice evolutions of the current vehicles. The Milan doesn't look like it has changed much. I'm not liking the tailights on the Fusion. The current models' taillights look much better IMO. The MKZ looks stunning! The MKR grille works quite nicely. Those tailights suit the vehicle much better.
If these pictures look as similar to the real thing, as Igor has stated, I will feel very optimistic abouts Ford's future prospects.