I think the Cayenne was a good idea, what I don't like is the exterior design (it reminds me of the first 996 version when Porsche had no money and they had to share tons of parts with the Boxster not to go bankrupt).
I'm still speculating about the reason of the "inconclusive", conservative and somehow ugly design of the Cayenne (especially the Cayenne V6 and V8) but maybe Porsche wasn't willing to risk too much money with a product they didn't know if it is gonna be succesful or not.
I'm pretty sure that the facelift and especially the second generation of the Cayenne will be a 100% Porsche design, at least worth this name.
The Cayenne V6 was a big mistake in my opinion, performance is ridiculous for a Porsche and when I had one as a loaner, I hated it. It felt underpowered, it was somehow satisfactory in the city but thats it. Not even close to provide a certain Porsche feeling. I'm afraid the Cayenne V8 is not much much different but at least you get a feeling of power but still not enough due to the excessive weight of this truck.
BUT: the Cayenne was a good idea, it found many customers worldwide and I even think that it may have led some of them to the "true" Porsche cars, the sports cars. I can understand people who don't like the Cayenne but trust me if I tell you: the Cayenne Turbo, especially the 500 HP powerkit version with improved braking system, is THE Porsche SUV among other SUVs. But I guess they couldn't have sold the Turbo only...too expensive, WAY TOO expensive.
I also think that the Panamera is a good idea because people who don't like the Cayenne and can't buy a Porsche sportscar due to family, business, etc., may get an alternative. But Porsche has to be very careful about the design, power and especially the weight. If the Panamera weights more than the Mercedes S-class, its not gonna be a winner. But it may stirr up the luxury car market because I can imagine that a lot of current BMW 7series and Mercedes S-class drivers would prefer to drive a Porsche limousine instead.
The Cayman is a different story, why should I lie: I don't like the Cayman. Not because it is a bad product, it isn't. But it is somehow a clever marketing trick to offer a Boxster Coupe with a fixed roof and a few horses more for more money, even using the 911's silhouette to attract customers who may find a 911 too expensive. Well, let me tell you something: if somebody buys the Cayman because of that, he'll regret it sooner or later. The Cayman can't replace a 911 and it won't. As soon as the more powerful 911 versions show up, Cayman drivers will be pretty frustrated because there definetely won't be a Cayman with 400 or 500 HP.
But if somebody buys the Cayman because he doesn't like the soft top of the Boxster and maybe even loves how the Cayman looks, he gets the hell of a car. The Cayman should be more rigid than the Boxster and in the right hands, it would be a very very fast little sportscar.
I still don't think there is a market for the Cayman but if Porsche thinks there is, maybe I'm just too dumb to see it.
The CGT is actually a race car which has been adapted to the street. I'm not sure the CGT is Porsche's technical masterpiece, I still think it was the 959 they built over a decade ago. If Porsche wants to prove they're top of the class regarding sports cars, they should build a 959 successor based on the upcoming 997 Turbo.
Porsche always has to be careful that new models they introduce are considered to be part of the Porsche family model line. People accepted the Cayenne because it was something new, something they couldn't really compare to other Porsche models. But with the Panamera and especially the Cayman, Porsche has to be very very careful. I still don't think that the Cayman will be a success because I bought a Boxster S for my wife (and I enjoy driving it too) but I would never buy a Cayman. Unless I would be forced to buy one...because I couldn't afford a 911. And then I think I would go for the Boxster S instead.
But it is of course a matter of taste, personal preference and how long somebody drives and enjoys Porsche cars. When I sold my 993 back in 1997 and went for a 996 Carrera 2 instead, a lot of people thought that I'm insane. Now the 996 is the most succesful 911 in Porsche history and I get the feeling that the 997 won't stay behind.
So maybe people need to give new Porsche models just a little chance to prove that they're really worth calling themselves Porsche. I still have my doubt about it regarding the Cayenne V6.