Check out the opening. One thing Blizzard does right at least is their cinematics.
New hero: The Crusader, meele character with shield and swords / hammers / flails (i.e. Paladin). One new Act: Supposedly much more of a "dark feel" New level cap (70): new skills and runes. Loot runs: Entirely randomized dungeons that take 15-20minutes to complete (for endgame). Nephalem Trials: Currently unknown. Expanded paragon system: Paragon levels are now account wide (applies to all characters), n