The "problem" isn't the Cayman itself, it is a great car and definetely a true Porsche, same with the Boxster.
The Cayman S is more Porsche than the Cayenne and this comes from a Cayenne owner.
So why do so many people have "issues" with the Cayman? The answer isn't too easy but I try to explain it from my point of view over here in Germany.
In my opinion, the Cayman product placement, marketing-wise, was a mistake.
First, Porsche shouldn't have named the Cayman CAYMAN but Boxster Coupe or even Boxster RS.
Second, Porsche shouldn't have placed, price-wise, the "Cayman" above the Boxster. The price tag should have been the same or even a tad lower.
Then, the whole engine thing 15 HP more than in the Boxster S, ridiculous. Now the engine power is even the same.
With the right name and the right price, the Cayman would have been a success in Germany. Right now, people over here think of it more as of as 911-wannabee or some sort of "foreign object". You guys may not realize it because people are kind and nice and don't always tell others what they truely think or in your country, the Cayman is a success.
So how does the future of the Cayman look alike? I don't know. I just hope that Porsche corrects a few mistakes they made, I'm not sure however that it is going to be that easy. With the change to the next generation Boxster, the Cayman may just disappear and the Boxster Coupe may arise from the ashes. I just hope Porsche is clever enough to do that. For the same price tag as the Boxster.
Finally a word regarding power: Porsche should definetely overcome the 911-power thingie and offer more power in the Boxster. If this is a problem for marketing, give the 911 more power and then add some more horses to the Boxster too.
330 HP in the Boxster or Cayman wouldn't "hurt" anybody, not even 911 sales in my opinion.
Please don't take this post as a provocation, I just told you what we're discussing among fellow Porschephiles over here in Germany. Since I also own a Cayenne Turbo and since my wife drives a Boxster S (which I drive too from time to time), I don't think I'm a 911 lover only.