I enjoyed BG1 a lot, and I have played it twice, the second time because a friend gave me its expansion, Tales of the Sword Coast (TOSC)
I have forgotten the number of times I have played SoA... And thanks to the many mods out there, and the NPCs I choose, each time it is somewhat different.
I largely agree with Fable; the game is far more complex in terms of story, character development, interactions and atmosphere. I think that the group interactions are a significant part of what make this such a great game, and they also make the game more realistic from a roleplaying perspective. One would assume that if a group of individuals are trudging about together for an extended period that friendships, animosities and romances are likely to develop
BG1's relative lack of dialogue and group interaction make it a far less interesting game...
But yes, it *is* worth picking up, because it gives you a sense of completion. Also, as people have said, there is something quite rewarding about being scared of a wolf
. You might even want to consider creating a character in BG1/TOSC, and then exporting them into SoA/ToB. This will truly give you a sense of the journey that your PC has made.