The Evo is super fun and the 2014 version is even better.
For the OP, I haven't ridden the Heritage but I rode the Cobra, Proto and SL (and Evo) a couple of weeks ago. I personally found the Cobra to be great carving on groomers - really locks into a carve well and I don't know what the fuss is about re switch, I had no problems riding switch on groomers or pow. Missing some 'fun' though. That said I preferred the Proto in pretty much all conditions but I like the playfulness and more involving ride in all but the lumpiest snow.
The heritage does sound on paper what you're after, but if you want less stiff go SL, if you want more playful/involving go Proto, if you want playfulish, slightly pow optimised(you say you don't ride this) board that still carves well on groomers get the cobra. FWIW you can lay down some fairly decent carves on an Evo, so rider preference is a big factor, most of the boards will do what you're after just fine once you get used to them.