Naturally its gotta be somewhat faster than previous gen, higher CC number by itself does not warrant anything, if it does not bring performance increase alongside it.... but as i said, its one of the parameters/properties of the GPU. Like VRAM capacity. Its usually stated on the box. Its one way to compare to previous generation. To someone, who is not hardware enthusiast, it now says its in some way inferior to what he already owns. And as you said, will this person look deeper inside to actually find out the card is faster, even though based on specs it should not be?
And then again someone like me. Lets say i own Titan X, hypothetically (i dont). But now i see the 1080 is say 25 percent faster, even though it has only 2560 shaders. Do you know what i think? If only it had 3200 of those (more than my Titan X), it would have been perhaps 40-50 percent faster. Now that would make me to want to buy it. And i know 3200 CC would have been manufacturable for Nvidia (if p100 is after all), the chip would just need to be somewhat larger (say 350mm instead of 320mm). Yet Nvidia decided that 25 percent perf increase should be good enough for me (cause somewhat better yields, higher margins for them). So yeah, in such case, personally i am inclined to think, screw you Nvidia.