OP: Imagine a standard D&D campaign. Now imagine that the highest-level monsters are goblins, kobolds, and whatnot. And you fight beholders, dragons, illithids, demons, etc. at the beginning. Only they are easily killed by a wizard with a knife.
Post #7: To be fair, this idea kinda makes sense. You're facing these giant, supernaturally gifted beings. They dont have to fight to survive, they're fucking monsters. But then you have these... things. These little lizards, who in a world where there are mind stealing multidimensional horrors, shouldn't even exist. But they do. They've learned well from the constant slaughter of their race from the monsters of their realm. All of the small humanoids have had to. The kobolds, the dwarves, the orcs, they all have had to learn how to easily take down the monsters which threaten their worlds. The small, weak kobolds have built up a method of taking out dragons by scampering up their backs, and hijacking the bodies using "weak" telekinetic forces or by implanting them with devices which render them nothing more than steeds. The entire world is built around kobolds having taught their methods of combat to other races, and selling dragons as steeds. All races are equally dangerous to each other, because they have had to exist together for such a long time. Its no surprise goblins are still alive: They know how to defend themselves.
So the Prime plane is the strongest, and the farther away from it a creature is from, the weaker it becomes. Summoning things becomes quite trivial, as even the weakest adventures could wipe out a city in the lowest hell (if they had some way of getting there).
Dragons are small lizards a la Pratchett's swamp dragons. Kobolds and Goblins are the redonkulous powers of the setting. I like it.
"Do not meddle in the affairs of Dragons.
For thou are crunchy, and taste good with ketchup.
... Err, a little more ketchup please ... The whole bottle?
Never mind, just pass the cow."
St. George: We heard there was a dragon operating in this neighborhood. We just want to know if you've seen him. Knave: Sure, I've seen him. St. George: Could you describe him for me? Knave: What's to describe? You see one dragon, you seen 'em all! St. George: Would you try to remember, Sir? Just for the record. We just want to get the facts, Sir. Knave: Well, he was, you know, he had orange polka dots... St. George: Yes, Sir. Knave: Purple feet, breathing fire and smoke... St. George: Mmm-hmm. Knave: And one big bloodshot eye right in the middle of his forehead and, uh, like that. St. George: Notice anything unusual about him?
Knave: No, he's just your run-of-the-mill dragon, you know..