No - I can say in no uncertain terms that WDW has not lost its magic. If someone handed me $5000 and said go anywhere you want with this money, I would choose Disney. If someone handed me $10,000 and said go anywhere, I would choose Disney twice. There is no place more magical and immersive than WDW.
I think the problem is that a lot of people went to Disney as children and had amazing experiences which are probably missing elements of reality now in their memories and so they hold things to an unrealistic expectation. And some people have gone as adults and had amazing experiences and were overwhelmed by it and their memories are probably a bit distorted towards the positive side of reality. What happens then is that people become addicted to WDW and get on forums like this with people likewise addicted and all we want to do is talk Disney; which includes analytics, opinions, experiences (good and bad), etc. By doing this, we can actually take the magic out of it for ourselves.
Reading through this forum over the years, some of the things I've read would make one think Disney has just gone down the tubes. And, I hated that when I would go back I would see all of these little things that I would have never noticed before. So, what I started doing was spending way LESS time on the rumors forum, and spending way more time in positive threads in discussion, trip planning, etc.
Actually when I saw the title "Has Disney lost its magic" (or whatever it was called), I intentionally didn't read it because I didn't want to hear all of the bad-mouthing. But, I'm glad to see that the consensus was no, because I wholeheartedly agree with that.