To the commenter who said Disney shouldn't have to wait for a big anniversary to plus attractions, which used to be the norm, I actually see this as the old norm returning. Avatar, Star Wars, an addition to the World Showcase, or any other land could each by their own count as 10 or more additions if one were counting opportunistically. Heck, Star Wars Land could probably be all 50 by itself. Disney doesn't need to plus anything to hit this marketing slogan target. Yet, the proposed improvements are widespread, diverse, and thoughtful. Surely they won't all come true, but that these are being discussed surely shows a change of heart compared to recent years. More to the point, none of the items listed are upcharges. And seeing as construction and closure limitations dictate that these improvements happen gradually over a number of years, I think it'll certainly feel like the old norm returning. Beyond the 50th is anyone's guess because we don't even know who will be running the company then let alone its direction or the state of the economy.
I absolutely loved what Disney did for Disneyland's 60th. The minor touches there were more than the sum of their parts. What a delight. Work there hasn't slowed down since then.