Memoria are ugly- but not because of the art (shoutout AV artists), rather their bland presentation in the game. Memoria are just illustrations slapped onto a dull unit border; when you select a memoria, the illustrations that artists put great effort into are presented as a flat png in the purple ocean of the UI. The art is downplayed by the lack of effort put into its presentation, and that calls for some sort of aesthetic rework.
Memoria's presentation would greatly benefit from integrating a card game-like border similar to a Yu-Gi-Oh or Pokemon. It could be 3D-ish in the menu so it can be rotateable and then be 2D in the game . Moreover, it would be cool for each card to have an aura emanating according to either their aura or trait within the menu. Small things like these can bolster the presentation of Memoria, uplift the illustrations your artists put so much effort into, and just give more aura to Memoria and their rarities. This would help match the Memoria system to the high quality your game boasts in all other forms!