recently, all of us discussing about stella and wand of star. i have an idea about colour zone. why not reverse the limit from “one colour must use” to “one colour cant use”? just add 3 more region in colour zone (inner ring). then, 3 single colour and 3 removed colour.
6 colour troops or weapon will have no more extreme advantage, so you will never meet 6 colour troops / weapon.
(I like stella and wand of star in PVE, so dont touch them)