I think what a lot of people here are forgetting is it's Disney...it's mostly G or PG-family oriented stuff (movies, tv shows, etc.) which targets about 80% of the USA household market. If you have kids (like I do), they will watch most Disney movies 98 times before getting sick of it.
Buying a Disney movie on dvd or blu ray for $20+ was a bargain, again, because the kids will watch it a zillion times over the year(s). Now that I can spend $70/year to have access to all their back catalog to be enjoyed by us 5 family members is a BARGAIN. I hope they have the Witch Mountain movies that I adored as a kid.
If you are an adult with 0 kids, it's very likely Disney+ is not for you. Even if it's free. Got kids?...you can't go wrong with Disney+.
Lastly, although I cannot make promises, Disney Customer Service is top notch and will not be like your cable provider or Netflix. Meaning, if you aren't happy, Disney will give you what you want (free service, refund, extra months, etc.). Trust me.