I`ll just leave this here:
http://www.youtube.com/watch?feature...&v=HEvThjiE038
Some of of the things that did not make it to the launch:
Ladders to climb up and down on.
Boss Hero-Death animations.
These areas "Forgotten Tomb" does not exist and "Leorics Highland" changed much.
Cinematic cut-scenes in a middle of a dungeon.
UI system: Mana as a resource for all classes.
Hovering healthbar on each and every enemy only visable while hover mouse on them
The Talisman (icon between the weapon slots)
Inventory style changed into the "tetris" style.
"Super block" by skeletons with shield did not make all the way to the release and was weakend.
Number 5 "Scroll of townportal / identify" was scraped.
Random people you click on that will follow you (like those in this video, not chicken warriors Act 3 included).
Minor Energy Rune and Elixir of Vitalty do not appear in Diablo 3 at all (see around 04:22).
Inaccessable gaps wouldn't work at all since not all classes could pass them. Animation was pre-fixed. Just like the death-animation on the siege breaker.
Girls dancing before they explode just to be summoned into a mini-boss, which just became normal monster later on.
And many other things!
Yes I`m sure they dropped all the things they announced at blizzcon because they didnt feel like it was good...yeah right lets make this game simplified so that we can attract as many casuals as we can just like we did with WoW and badge gear yey marketing strategy...