I agree with those who miss the Peoplemover -- partly because it was just a nice way to sit and rest for twenty minutes while getting a nice scenic tour; partly because it was one of those "land of the future" things where you could think "I might be riding one of these to work one day!" (Whereas I know I'll never be flying to the moons of Endor.)
I have frustrated memories regarding the Mine Train, in that the last several times I went to Disneyland while the attraction was still there, it was closed. (In its later years it tended to run only on weekends and during peak periods, and I happened to go on off-season weekdays.) So I'm just sorry I don't have better memories of it.
I may be one of very few who misses Videopolis. I spent a lot of nights there during the summer of...what year was it? 1985? Dancing like a maniac to "Two Tribes" by Frankie Goes to Hollywood as the fireworks shot off, then going and riding "Adventure Through Inner Space" to cool down (it had the best air conditioning in the park). But it wouldn't be the same today -- I'm older and it wouldn't be that 80's music.
From the same period: not so much an attraction as an atmosphere. I really miss the feel of the park's west side on those summer nights. After the sun went down, most of the crowds tended to congregate in Tomorrowland and Fantasyland, and along Main Street for the Electrical Parade. Around the Rivers of America, it was just so peaceful and uncrowded. In fact, many a night, if you started about the time of the first Electrical Parade, you could ride the Haunted Mansion, Pirates, and the Jungle Cruise in rapid succession, with no waiting at all, and lines for Big Thunder would be maybe ten minutes. It was great! (Alternatively, you could board the Mark Twain at the right time, and it would stop on the far side of the Island for fireworks viewing. Not the best vantage point, but one worth seeing a few times.)
Of course, from the park management point of view, I can see where empty streets are Not A Good Thing. So now, with Splash Mountain, Indiana Jones, and of course, Fantasmic, that area of the park is packed solid in the evenings too. They're all good attractions and bring in the money that keeps the park open -- but I still can't help missing the quiet.