There is a discussion on the geek about Fantasy Flights art for their reprint of Princes of Florance.
http://www.boardgamegeek.com/thread/110579/page/1
The gist of it is that FF is using their regular stable of artists and the artwork looks a bit more "Modern Fantasy" than "Renisance."
The artwork does look a lot like other FF offerings like Citadels or Descent even. (And personally I don't think it fits the theme of the game very well.)
It does bring up some interesting questions though. Should each game have its own specific feel and look to it? For a game company is it better to develop a brand "Look"? Or is it better for a game designer to develop a brand look as well? Look at the success of Cheapass games which has a pretty strong design image.
I think an elegant example is Doris of Doris and Frank fame. Her art remains distinctive yet at the same time very fitting to the themes of the games she illustraits. I think in this resprect she is kind of the holy grail of art direction in a game artist.
In a world where name recognition is at least as important as quality I think this is worth talking about.