I read through the whole thread and many people commented on the things I also miss dearly:
Adventures Club
Horizons
Word of Motion (I actually liked this better then Test Track)
River Country
Those are my big ones, what annoys me is that many of these things are left behind. I can understand replacing with something new / improving but to just up and close them when many are still enjoyed is questionable. WDW is a huge place, it's not like there is a shortage of space to expand the parks.
Why did River Country have to close, though it would have some expense counldn't they refit the park to use recycled pool water? It had a nice "Ole watering hole" feel to it. I love the new water parks but it doesn't have the same feeling to it.
Why not keep Adventures Club and move it to Animal Kingdom? It fits in perfectly and could be a reason to draw crowds there later in the evening for lite appitizers / drinks.
I also didn't like the name change from Dixie Landings to one big Port Orleans complex.
I also miss the real wood guns (I had a pistol) from the PoC ride, I got one as a child and it was one of the favorite toys for years.
I guess what most of us remember is not so much WDW of the past but simpler times. There wasn't daily non stop flights to WDW, airfare wasn't as affordable, most family vacations were done via driving so going to WDW was a major trip. You certainly didn't have the international business they do now. Tastes change, the demographics visiting change etc. At the end of the day WDW is a business (sadly).