Addition to Armory Mode
In the Armory Mode module, under Item Level, there is an option to enable "Item Level Coloring" which changes the color of the item level text to match the rarity of the respective items.
I propose an additional feature to color the text based on your average ilvl such that you can quickly identify your highest and lowest ilvl gear based on a color gradient.
See this screenshot I have modified from my own gear to show the color scale I propose.
I used conditional formatting in a spreadsheet to figure out the colors for the ilvls.