Hey madtoaster. A straight ramp, is a ramp which has a few colors, anything from 2 to 32 which are all varied in terms of LIGHTNESS, but the same in HUE and SATURATION. This wastes a lot of near-shades that could be unified on a sprite, and also looks very boring and lifeless. Hand-edit every shade you use, play with its saturation and hue, try to repesent more color and warmth or coldness according to the design you're going for. It doesn't have to be THREE SHADES FOR FACE, FIVE FOR CLOTHES. It can be, two shades for face, 3 for clothes, one desaturaded dark blue for both face and clothes, blue from eye eyes highlight on the clothes, that extra gray can be dithered on the pants for a dirt effect, so on.
I've seen your CG work over at punaji and for all they other merits, it seems you haven't given colors much thought in that field either. Half of pixel art is being smart with your colors.