Huge world/exploration like Skyrim
Creature interaction & behavior like Skyrim
NPC depth with world puzzles like Majora’s Mask
NPC conversational depth like Dragon Age
Romances like Dragon Age (with notable improvements!)
Music like Skyrim & Zelda
Tone/mood like Majora’s Mask 
Political depth like Skyrim
Dungeon puzzles like Zelda, but harder generally
Non-combat related activities like that Harvest Moon dungeon RPG thing
Combat like Zelda
Boss difficulty like Dark Souls 
Boss complexity/inventiveness like Warcraft raid bosses
Leveling like Skyrim