Goddamnit, brb downloading SWG Pre-CU emulator.

That game had everything.
Huge open world(s).
Labyrinthine dungeons.
Space Combat.
Pets to be tamed, bio-engineered or crafted (Droids).
Player-created mounts (tamed pets, engineered pets or speeders/bikes).
Open world housing.
Completely player driven economies.
One of the most varied class/profession systems in the game (Should I be my Bounty Hunter Teras Kasi Master? My Squad Leader Combat Medic? My Ranger Creature Handler?).
A truly in depth crafting/resource gathering system (your EH17 Blaster is not as good as my EH17 Blaster because I spent the time tracking down non-ferrous metal with higher conductivity than yours and paid a smuggler to modify it for enhanced fire rate).
Support classes that were damn near essential (Dancers/Performers/Medics).
Open world PvP that could be Optional or Forced (depending if you chose to be faction-aligned, overt or covert).
Perma-death. Oh you spent 3 months grinding to become a Jedi? That's nice. Shame you let yourself be tracked down by a Bounty Hunter and his Ranger friend (though tbh, if you died to two people as a Jedi you sucked).

All this, and not a single instance.