Correct. I'm relieved knowing it's normal, but not satisfied that it's normal.
As with most things in life, it's really not possible to expect perfection from every single aspect of every single individual component in a mass-produced device. LCD panel displays included.
Solution to your problem: turn on some bloody lights.
Don't sit in a totally dark room looking at your monitor. It's bad for the eyes doing that anyhow.
Consider that these panels have roughly 3.6 million pixels, and that each pixel (wich is very small in of itself) consists of three microscopic sub-pixels, each controlled by two transistors etched and vacuum-deposited right into the glass panel itself. That's over 11 million sub-pixels and 22 million transistors spread out across roughly 60 by 33.5cm on a thunderbolt display.
That's over 2000 square centimeters and a lot of room for error, and yet performance is at least in my opinion very uniform on the whole.
That modern LCD panels work as well as they do, and give the kind of performance we get, for a relatively low price all things considering, is quite amazing at least to me. Maybe that's because I've followed video and computer development since the early 80s, so I remember clearly what we used to have to settle for in the past. It certainly wasn't better than today's stuff, that's for sure!
In 1998, I bought an Eizo 19" CRT monitor; it pulled around 250W from the wall socket, it weighed 28kg, and it was probably at least 40cm deep from the front glass surface to the rear edge meaning it was a real back-breaker hauling around. It supported a pixel resolution of 1600*1200, but using it at that high res wasn't comfortable, text was small and kinda fuzzy in the outlines, and moiré in thin vertical lines caused by the trinitron tube was annoying. Usually I settled for 1200-ish rez to improve readability and pixel sharpness.
Other peculiarities included heavy bass sound which could cause the entire front aperture to "shimmy" (with very strange visual results, if you've ever witnessed it), and of course, the monitor needed to be degaussed regularly and carefully calibrated to compensate for the earth's magnetic field and other sources of distortion. The working temperature of the electronics controlling the electron beam also caused shifts in image size and position as the unit heated up after being turned on... On top of everything else, CRTs also suffered from "backlight bleed", or rather the analog equivalent, and it was much more visible than on today's flatscreen displays when turning up the brightness high.
Pretty much all of that we won't have to deal with anymore with modern LCD panels. They're much lighter, pin-sharp and draw much less power and can be made a lot bigger too without cost and weight galloping out of control. If you were in the market for 24" computer monitors 10+ years ago, you probably remember that such displays were enormously expensive, very bulky and monstrously heavy.
Today we can buy even IPS-panel 24" or even 27" LCD displays of that size for a fraction of the price, and most of them probably weigh around 5-6kg or so. Isn't that an improvement so say!
Be happy that Apple seems to have a zero-defect policy with regards to stuck pixels; you don't always get that from other manufacturers. That you get some backlight bleed in the corners is just something you will have to live with. It's inherent to the technology used, and it'll stay until we switch to some other panel type like OLED for example, where every sub-pixel is a discrete light emitter, which we'll undoubtedly find new or even the same issues with as well!
