As others have said, cigars are color sorted by the box just prior to packaging, so there will always be some degree of color differences from box to box.
The amount of variation will depend on the capa... For example, far less deviation in Ecuador Connecticut Grade 1 and Grade 2 wrappers vs. Ecuador Habano wrappers of the very same grades... it is a natural leaf and part in parcel of that is variation in color, texture, sheen, etc... The issues become more pronounced in even heavier leaf varieties such as Stalk Cut Habano, Nicaraguan Sun Grown Criollo and Broadleaf.
As a tobacco man, you can get the color to even out more, but often that requires you to over ferment the wrapper (IMO) which means you are sacrificing oils which in turn means you are sacrificing flavor and aroma in order to achieve a more even and often but not always, a darker hue.
Personally, I am ok with color variations... my personal practice has always to be to arrest the pilon when the tobacco is combusting properly and is at its peak flavor and aroma wise.
I like picture perfect cigars as much as the next guy, but ultimately I prefer they be at their optimum for smoking enjoyment.
BR,
STS