The thing I miss most about the good old days, is the ability for children to go into the cokpit (and depending on the crew, the ability to sit in the captain's seat and 'fly' the plane!) I feel sad that our children will never get to do that. I also miss the quite random upgrades, not for being a frequent flyer etc, but 'just because'! I was upgraded along with my parents many years ago on a trans-atlantic flight 'because we have some unexpected room up front, and we think you guys would enjoy it'! Oh, and I miss extremely polite flight attendents too, but I can't complain too much about recent flights, they seem to have bucked up their ideas again - amazing what a recession can do for job security! I miss not being allowed liquids (weird and wonderful alcohol, or even, in my case, elderflower cordial and soft cheeses (yes, I was told a round of brie constituted a liquid!) ).
I don't miss 'smoking sections' (like having a peeing section in a swimming pool!), the lines out of the door for check in on large / busy flights (online check in is fab!) or getting soaking wet while boarding up outdoor stairs (although Frankfurt and Rome have both had me doing that recently).