The slug things are quite cheerful. And the piggies have a happy ending, unless you have a hankering for a self-propelled barbecue.
The slugs developed some sort of mental disorders from being sluggos for all that time. You can't just go around going "blrt" and say you're the royal wine server or whatever. They're obviously in need of therapy.
And as for the piggus they
did have to spend several centuries quite literally on fire, which needless to say is an amount of negative stimuli to turn anyone's brain to mush. The only thing they should be able to say when perpetually burning is a low wheeze because they would definitely have broken their vocal cords permanently from the non-stop screaming. Torture isn't cool, kids.
I think this goes deeper, I think Larian just hates animals. Swen put a "chicken" in a microwave for instance. That guy's crazy.