Underused ideas

• Imoen.org girl joins the party and sells plumbing products throughout Amn, Brynnlaw, and the Planar Prison.
• Extraplanar travel
• Meeting characters from other games
• The spelljammer ships could be more than decorative
• A non-humanoid NPC
• Dwarven, halfling, gnome or half-orc NPCs
• A NPC that's blind, deaf or mute
• Non-joinable NPCs with their own lives. There are a few, there should be more.
• More extensive and meaningful NPC agendas.
• NPC's that have a FULL life on their own.
• An actual NPC interested in the PC's taint without trying to kill him for it
• Engagement gifts for the romance-able characters... not just Jaheira.
• New spells (?)
• A normal dungeon (no quest links, just go in, kill monster's and loot)
• The world does not react nearly enough in response to CHARNAME's actions, a problem in most CRPGs.
• An explanation for why a city needs all those weapons dealers, and why almost all of them stock magic weapons.
• A mage/smith guild to justify the abundance of magic items
• Empty wilderness areas between quest locations in BG2, similar to BG1.
• Being able to generate a random familiar instead of being assigned one by alignment.
• Psionic system.
• Politicking and research.
• Infiltration and subversion as tactics. It is a major theme of BGI but gets lost in SoA.
• Situations that are unwinable using battle tactics, or where the best you can hope for is a stalemate.
• A villain who avoids combat.