Things that other games did right~

[Spuffin]

TERA:
-Customization
-Open World Content
-Innate Controller support

Ragnarok Online:
-Music
-Class Progression
-Card Mechanic (BUT NOT THE DROP RATE.)

Final Fantasy XI:
-Music
-Story based progression - Doing missions to unlock end-game content and areas as a reward, nothing beats this.
-Job system - Heavily interpretable by the community, however.
-Storyline
-Party/Alliance content.
-Open World dungeons
-BCNMs
-Limbus
-Sky
-Nyzul Isle
-Salvage (excluding drop rates)
-Walk of Echos (excluding drop rates)
-Zeni Notorious Monster system

Unlockable areas through mission completion was a very nice feature~