Like read a dictionary, do you even know what the word means? Smartphone design has more or less stabilised and unless holographic hard light devices, like the ones we see in movies, are invented, I don’t think there is anything left to be done on the hardware side expect adding gimmicks every now and then.
It’s a non-complaint so that people who don’t understand what the issues have something to say. The correct answer is putting them on the spot and ask them to be precise. What specific innovation is wanted by them?
(I’ve sat through waaaaaaaay too many feature planning meetings to be patient about this.)