I know everyone hopes for new colors when an Exo appears or someone rents a new Sovereign. There are only 255 possible colors for each item and those will eventually be exhausted. New colors will not be possible at that point. With each new color that appears, there’s less & less of a statistical chance that a new one will happen. That’s why it seems like it’s taking forever for new colors to show up.
(Exos provide other exclusive resources like goo kernels, resin, petrolim, ichor, kindling, lucent ores, & plant seeds.)
Best case scenario would be that Monumental will unlock all colors for building. They would then add in new resources like mobs, drops, plants, treasure, ores, unique biomes, etc that would be exclusive to Exos.
The other option would be to complete update 249. Make it so that all items can be spray tinted for building. I don’t know if they plan to keep this update or if they are going to scrap it. It would be nice to have the melee weapons, shields, and full 359 skill sheet in this type of game imo.