I think the key is how frequently these things occur (1 in 1,000 rooms? 1 in 100 rooms? 1 in 10 rooms?) -- and unfortunately, NONE OF US CAN KNOW THIS.
A valid point. Disney is so huge that there could be a lot of horrific reviews and the grand majority of people could still be satisfied customers. I also think that the cost of Disney rooms create expectations that aren't likely to be met. While I often compare the onsite resorts to oceanfront units, in that they're smaller than you'd normally get for the price, there's also the fact that people staying onsite are in a sense paying for most of the public spaces at their resort, as well as all the resort transportation. Your average hotel charging Disney Deluxe rates may have a shuttle service, but that's about it; Disney picks people up at the airport and takes them everywhere else (onsite) that they want to go, every day of the trip! I expect the extra cost of the parks opening an hour early or staying open an hour late for Extra Magic Hours also comes out of the hotel budget. Does Disney slap a nice big profit on top of all that? No idea, but I do think their basic costs are higher.
The majority of the negative Disney resort reviews I've read over the years are by first timers who are shocked at what they got (or, more importantly, didn't get) for their money. Those reviews tend to be long on outrage, and short on specifics. Another sizeable chunk are reviews by people who've gone to Disney a number of times and then had a bad experience. Those reviews tend to have a lot of specifics, usually one or two major issues, followed by all kinda little ones. Another chunk of reviews, overlapping those other two categories, are what I consider "shakedown issues" -- the various plumbing issues in the new Poly Timeshare units; the problems in Bay Lake Towers the first year or two. Can't remember all the specifics with Bay Lake Towers, but I know Disney made right on some of the owner's complaints (re-categorizing the view status of various units, for instance). It does seem to me that things usually settle down after a year or two, but whether Disney fixes most things, or whether word gets out and most people who don't like some aspects know to avoid those places, is another thing we'll never know.
I hear a lot of gripes in the Timeshare world that Disney units are shabby and disappointing -- this from people who're trading in, so paying far less per night than the average Disney customer -- but DVC units have been fairly tough to get through RCI without an ongoing request. Then again, maybe that's why DVC switches from RCI to Interval International periodically; to keep interest up.

As soon as DVC gets "too easy" to trade into, they move into an entirely different market, full of people who've been wishing they could try out DVC units just to see what they're like. Whether Disney's good at running hotels or not, they're sheer genius when it comes to marketing.
