Best recommendation I have: Take it into an Apple Store and compare with a display model. See if yours is noticeably worse.
Every screen has its quirks. My Dad just got a Samsung 9500-series 65-inch TV. Cost $3700 Canadian, on a recent sale near Black Friday. It has lots of backlight bleeding, but the picture is still amazing. The 13-inch MBP I'm on has darkening just at the very right of the screen, as the screen meets the bezel, the whole way down (very slight). My old 11-inch Macbook Air (2011) had backlight bleeding or darkening (I forget which) at the bottom of the screen horizontally near the bezel. My iPad 3 (and many iPad 3's) had weird backlight pixel clusters that were only noticeable when the thing was black.
Unless if a screen is OLED or Plasma, backlight seems to be an issue.
With that all said, don't put up with defects if you find yours is functioning worse than average.