Yeah that's a pretty solid summation. I am still on the fence this year but am starting to get the "itch" for the first time since picking up my 8+ on launch day. The screen protection I had installed the day I got it is still on there, the lady who installed it at the Verizon store did it by hand. I have installed other screen protection by hand with no problems. If I bite the bullet it will be done by me or by a store employee by hand.
I'd like to think that Apple might have tested this when developing the phones or at least have had Belkin test the install process before offering it. Either they did and didn't receive these results or brushed it off. Who knows, your guess is as good as mine because that ship sailed. On that note I applaud the OP for reporting it and for getting a new device to replace it. I definitely agree it should have been replaced so good on Apple for doing that. If that happened to me the first time, I'd have never have let someone do that by machine the second time and that's where the confusion sets in. I understand the OP has a shaky hand and is unable to do it, so there's that. Pretty sure there are other options though to have screen protection done. Whatever the case it's good to get this out there so others are aware of what might happen.
I agree with a few of the comments. No need to obsess with minor imperfections--unless it impacts performance, that said out of the box, a phone or a car or whatever, should be as close to perfect as possible. Wear caused during ownership is one thing--that's life. Out of the box, brand new, whatever it is, I'm expecting as close to perfect as possible. Apple made it right in this case and that's a good thing. Same way as when my auto dealership scratched paint on my vehicle, they fixed it, no cost to me and provided me with a rental.