Yes, you're absolutely right....and changes in ambient light exacerbates the problem too. Fluorescent lighting make it appear a lot worse than it it. When I'm back at home (incandescent lighting), its better but still visible without looking for it. If I can see it in everyday use, its a fault in my book. My phone has 4 of these blemish points too....but they didn't bother me much as I could only see them when I looked for them.
I thought I could live with it but after examining friends iPhone's I've decided £789 is too much for a phone with a uneven screen. Just finished with Apple online support chat and they agree, the screen shouldn't be like that so they've organised an express replacement for me. I really hope this one has an even backlight.
Fingers, toes and buttocks crossed!