Before MMOs became glorified Diablo Clones with tacked on multiplayer elements, MMORPGs were games with mechanics that fostered, encouraged, and required a cohesive social network that resulted in a dynamic and player driven sandbox.
SWG features player housing, player run cities, open PvP over teritory through the Galactic Civil War social classes like Entertainer and Doctor who interacted with the community and gave the best buffs. If you didn't talk to those players you got nothing and thus weren't playing optimally. Encouraging being social. SWG had the best crafting in any game ever. Instead of Good resource < better resource < best resource you had to do surveys to find out about resources with different properties. Then find out how to combine them into items with the stats you're looking for. There were thousands of different resources across several planets and multiple different ways to harvest them.
To be a good crafter required experimentation and insider knowledge. Beyond armour and weapons you had droids, furniture, clothes, spaceships, and buildings. And because of the way the XP worked you had to specialise. Meaning different crafters had to fill different niches and rely on each other to fill gaps. This also meant reputation was everything and if you were a sperg with a bad attitude you didn't get far. Actual social consequences for your bad behaviour that wasn't just powertripping jannies banning you for wrong think? No wonder the game flopped.
If you got bored of the base game you could go out into space which was a fully functional space sim inspired by X-Wing and Tie Fighter. Also it had seemless multicrew spaceships with complete interiors in 2004 whilst Elite Dangerous struggles to add space legs to barren and featureless planets in 2025.
Also SWG in it's original form was classless. You had a limited amount of points to put into whatever skill trees you wanted. So you had to specialise. Of course when people figured out the grind to unlock Jedi everyone started doing that instead of playing the game. The Combat Upgrade could've fixed this but was a half measure. The NGE was a bad and heavy implementation of the good idea to address the fans request to fix SWGs many problems with combat and questing. But pre CU, CU, and NGE are all better MMORPGs than WoW. I will die on this hill.