In spite of distorted memories of so many, the overall look of MK in particular, and the entire resort in general is so much brighter, cleaner looking and sharp then it was in the early day. The quick service food places carried packaged sandwiches like you find now in any gas station, convenience store. The technology for the new stuff is far advanced.
Many have mentioned FP. FP while good if you had one, was before when it first started and even with the new system still limited in its numbers. Yes, most of the lines back then were fairly long in people, but, the wait generally was shorter. You got in a line and it moved continuously. No long delays while you watched busloads of people legally cut in front of you. A whole lot less frustrating back then because everyone was treated equally and first come were first served. Now if you have a FP your time in that particular line is less, but, since you cannot get a FP for everything during your visit, you will lose all the time you made up from FP waiting in Standby in the other lines. There is no real improvement overall. It is just an allusion of time saving, and we all know how good Disney is at allusion.
So generally, many improvements have been made, but, not all of the things that were established were really as beneficial as everyone seems to think they were.