The display on the Nokia 6 has a strong cyan tint, which produces unrealistic colors and bluish whites. This problem can easily be fixed by adding a color temperature adjustment functionality. That will not only improve the user experience of the existing Nokia 6 users, but also appeal more to future potential customers. Here's an excerpt from a Gsmarena review which strongly resonates with my request
"The global variant doesn't have any display modes or color temperature sliders, and in its single pre-defined setting manages an average DeltaE of 7.2 with a maximum of 11.7 for white - white is strongly shifted towards cyan. The Chinese version has three modes, and, when set to Warm, can reproduce the sRGB color space with a DeltaE of 3.3 and reasonably accurate whites, which is something we appreciate."