Do you get special plots and quests and character interaction with npc's where they start talking to each other like in BGII?
Arcanum is Arcanum. BG is BG. Nope... Arcanum is more like Fallout2. NPCs won't start conversations on their own, and you won't have lots of NPC-related side quests. Though Virgil may give you one little side quest, and he has some opinions about some NPCs.