Having driven the 2.7 without the IMS issue (one of the few modern Porsche engines I don’t actually know the code number for off hand ), albeit in a Boxster rather than Cayman, I tend to agree with you. I preferred the older engine, it seemed a bit more lively, but then the new 2.7 was the only 9x7.2 lump NOT to get direct injection, which I’m guessing is what makes for a radically different feel.
Is it slow? No. It is a very different engine to the V6 in the Zed though, and yes you absolutely do have to rev it to make the most of it. The beauty of the Cayman is the chassis though, and how deft the car can feel under you. The 2.7 just needs a different driving style, but after having driven an mx5 for the last couple of months with much less power, I can promise you that the 2.7 is far more capable of overtaking
Work the engine and gearbox a bit more, don’t be afraid to use all the revs all the time. Shifting down to where the revs are at 4000rpm is a pleasure, not a chore As an aside, in terms of running costs my 997.2 was cheaper to run than my Zed was, and likewise the 987.2 Cayman R my brother has after his Zed was the same.