Have you ever noticed a lawn, some patches of which grow thicker, or longer, than the rest? I thought so. Does it bother you? Me neither. Would it bother you if such was the case with your face? If you're like most guys, this is precisely the predicament in which you find yourself. Buck up! There's hope! Read on.
For several years, I lamented the imbalanced distribution of hair across my face: the goatee area is markedly thicker than the cheeks! Then I noticed that I was not the only one. This is the case with most men. For the first couple months of a beard's life, the goatee/mustache area can be several shades darker than the rest, resulting in a two-tone effect. Two-tone patterns can be aesthetically pleasing if Bibles are in view, but on your face?
Although there's little that can be done for those first couple months, there is a long term solution: trim the goatee area shorter than the rest. I call this "manual face balancing."
For me, for instance, a #2 over the goatee and #4 over the cheeks works very well, if I'm keeping my beard shorter. For a fuller look, I've kept the goatee at a #5 and the cheeks at #7. You see, the proportions can close in as the beard gets longer.
I've never grown a very long beard. If I ever do, I suspect that all such balancing will be unnecessary.