Just had the idea today.
What if, there was an option in the portal GUI that allowed us to select the color for the portal when it isn’t loaded.
Currently the default color is blue (with some exceptions). Although it is a pretty blue I have in the past and currently now wish i could set a different color in order to match my portal room theme.
Could just be similar to the color options for color choices with paints etc.
left or right arrow to swap color and just hit save to lock the color in.
Color is based on the atmosphere on the other end of the portal AFAIK
shucks…so i doubt it would be updated :s
Viceroy should be able to choose the color IMO. Perhaps from a range of colors - say blues for easy atmospheres, reds for nasty atmospheres.
I mean… you sort of get to do that with sovereign planets… 
255 colors for portals, particle effect /different ‘shimmer’ for atmosphere
conduit owner decides. there’s no good reason why they must be certain colors, the atmosphere thing is helpful for like the first 1-2 hours, could be replaced with something else
EDIT: to make it more interesting (and the transition less painful) add ‘Gleambow conduit’ (works the same, but lets you pick color, craftable as event item)
icon for every atmosphere type can be added to be shown when player looks at portal, (just to make it more flashy than the text description)