"Going to sound obvious, but they should stylize when it works. I mean stylizing had clear benefits in some cases (Ghostbusters), but in others companies have tried to stylize for the sake of having something cartoony, and it just blew up in their faces (Madden 10)"
That and Madden 10 was apparently too simplified compared to even the past Wii Madden games.
Also, as pointed out, Call of Duty is selling well with realistic graphics, even though the critics still put them down.
A flashy-first game is awesome when it comes out. A great-first game is awesome forever.
Plus, just for the hell of it: Kelly Brook at the 2008 BAFTAs