Draconian stats could be a good fix for my current campaign. Dragonborn came from Bahamut, theoretically; so what do you get if tiamat decided to make a humanoid race? Sort of like how Orcs are corrupted elves in Tolkien.
I do want to say that I think horror at seeing a Sivak transform into oneself is a bit silly. Maybe there's some sort of psychic echo causing damage, but otherwise it's not going to fool the person who killed the Sivak; unlike the rest of the world, they are 100% sure that they're not the one slain.
I'd likely change it to a psychic echo that zaps the killer; maybe make it a close burst 3, plus ranged if someone hit them at range. That would be nice & brutal.
Fable 2 has a nifty answer for goblins, in that they're missing children kidnapped by other goblin-critters (namechange, same concept) and morphed into more of the beasties.
I like this, and it's a good reason for why goblinoids like hobgoblins are slavers: they capture humans and transform the adults into hobgoblins. Goblin-goblins are what come out when you take children and put them through the process. The transformation is permanent, and the goblins produced are automatically fully grown adults of the species capable of breeding more of their own kind (thus not all goblinoids slain are humans, whether adults or children; they could be offspring). Like in the move John Carpenter's The Thing, whatever they were is no more, now they're the alien.
Player-character goblins could have some memories of their past lives (usually this is eradicated by the change) and act upon their earlier motives.
Bard Taunting: yeah, I don't know what to say. sorcerer's Chaos Bolt makes sense: it's a bolt of something. Should be Force, but it's Psychic. Making someone embarassed enough not to fight isn't helpful for Solo monsters in a serious campaign, or stone golems... excepting that one scene in Venture Bros.
I'd like an instrument that lets the bard zap them. Seems a bit more realistic than name-calling someone to death.