As a practical matter, relative directions are already hard enough, where I might say that Colorado is east of California, and California is west of Colorado.

To use +/- East would mean there’s now just a single symbol difference between relative directions. California bring -East of Folorado, and Colorado being +East of California.

Also, we need not forget that the conventional meridian used for Earth navigation is centered on Greenwich in the UK, and is a holdover from the colonial era where Europe is put front-and-center on a map and everything else is “free real estate”. Perhaps if the New World didn’t exist, we would have right-ascension based system where Greenwich is still 0-deg East and Asia is almost 160-deg East. Why would colonialists center the maps on anywhere but themselves?