there are still two pages to read, but i want to comment on this: the disney "magic" is largely subjective, but really referred to the disney difference; the attention to detail that existed at WDW that you couldn't find at a six flags, or busch gardens, or universal. so, yes, i do believe you have to experience the other parks to see if that difference still exists.
i was a long-time disney apologist. i went to universal once in 1995, then not again until 2011 because my wife wanted to see WWOHP. even then, i was uncomfortable to even be stepping foot in universal. fast forward to now and i've been at UNI twice in three years and am planning another trip to see potter phase 2. why? simply because there's a lot more, what i grew to know as, "disney quality" at universal than there is at WDW nowadays. any lifestyler who forsakes other parks to sing disney's praises is doing themselves and their readers an injustice.
I have seen things over the last two years at parks from SWO to BGT and BGW and Knott's -- and obviously UNI and IOA -- that are much, much better than WDW. Some small, some not so.
There was a time not all that long ago when nobody touched WDW on pretty much anything (except perhaps cost). It feels like ancient times, though.