Everyone is seeking a signature "face" which explains the current Lexus situation. CAFE (and other world fuel economy standards) are affecting overall design these days, and in fact aerodynamics are the reason the D5 all but lost its stepped roofline. Pedestrian impact survivability requirements are also largely responsible for wrecking the faces of the current crop of vehicles.
I think more than anything, Land Rover recognizes its dual position as a Premium/Luxury (Land Rover/Range Rover) brand today and the way to capitalize on that is through "more accessible design." Which to me means less polarizing, more common.
From a pure design perspective, the current stuff all looks really good in isolation. But in the context of the company history, they don't carry forward much heritage; in the context of the larger marketplace, they look a little too much like other more common vehicles; and in the context of the current model range, they all look a bit too much alike.