Mr. dgcatanisiri (try saying that 5 times fast) has the right idea here.
KOTOR1 was made to play and feel like a Star Wars film:
KOTOR is cookie cutter Star Wars - Chosen One narrative, evil Empire versus a band of ragtag misfits, galaxy-threatening superweapon, evil overlord going "mwahaha!" and probably marking out specific time in his schedule to kick puppies and steal candy from babies.
It's easy to see who's the good guys and who's the bad guys. Light is good, dark is evil.
You don't need to think to understand what's happening, and that's not a bad thing.
The plot twist was, is, and forever will be one of the greatest moments I have ever experienced.
KOTOR2 is a thinking person's game.
To be clear, KOTOR1 did not fail by any means, and it's not as if KOTOR1 is lessened by KOTOR2, but KOTOR2 has made me really think like no other game that I know of.
Kreia especially is by far the most memorable companion I have ever had in any party in any game. She may not be my favorite, and I wouldn't necessarily want her watching my back, but she has the distinction of staying with me no matter what game I play.
I can hear her now:
*help the orphan find his parents*
"You should have let him struggle on his own, by robbing him of that experience you have weakened him!"
- Influence lost: Kreia -
*Attack the bandits outright*
"I would look at all the possibilities, see the strings, instead of severing them all outright!"
- Influence lost: Kreia -
Especially with the Restored Content Mod, KOTOR1 and KOTOR2 are the ONLY games that I will actually buy twice.
I had them on CD, loved them, but then the CD's didn't work, so I bought them digitally.
I don't buy the same game twice, but I did for KOTOR1 and KOTOR2.