As Jeremy Clarkson attests, Porsche are the employees the laziest designers in the business. (Other companies have designers that just don't have the right eye) Looking at the 911, it has remained essentially the same since its initial inception in 1963. Even when fresh, this new model borrowed heavily from the 356. The Boxster also draws from the 356 and the Cayman barely deserves to be called anything other than the Boxster Couple. All of these models, have engines behind the driver. (I don't want to argue about the mid verse rear engine/Boxster verse 911 debate because it isn't relevant here). These designs do not call for the standard front engine archetype with a grill and higher hood but rather a low aerodynamic schnoz.
I do remember the other front engine offerings of the 928/968 etc but these were still low slung sports cars that could "borrow" the predominant design language from the existing models. I would argue that the 928 is as unresolved as the Panamera or Cayenne, having a rump only a mother could love. I don't even want to get started on the rear of the Panamera.
Where does this leave these new front engine Porsches? Look at the Cayenne, across the model range, every iteration have a different front grill/intake/bumper assembly much like you see on the 911 range. Do you see BMW changing the shape of their trademark kidney grills between the 328i and 335i? They rely on a design heritage for the model and then tweak other aspects. However, while 911 has a distinct silhouette that can be easily recognized, Porsche has never created a Front Engine Design language. (Maybe because they're lazy) The differences in the bumper correspond to the increasing performance across the range. I think that on a Front Engine vehicle, Porsche needs to develop a standardized grill/bumper design language that can be applied to all models. They can still change aspects to indicator performance. The Lamborghini Estoque concept suffers from a similar problem, yet the angular audacious Lamborghini language seems to adapt better overall. Aston Martin doesn't suffer from this problem because their design language is based on front engine designs.
Porsche is going to struggle with styling until they are able to successfully develop a coherent language for their front engine vehicles. They should look to signature elements in Porsche's history. I would start with the ovaloid grill the the engine cover for the 911, round headlamps, and the intakes from the turbo.