"There, once and ever, lay a place of perfect obedience. A park-like land of rolling greens, golden oaks, unbreakable fealty, it shall not ever change. It cannot ever change.
"There will always be a vulpine Queen. Two ursine Dukes will bristle and binge. And the cygnine Countesses? Four castled ponds require four of them too. How could less than eight feline Barons hope to adequately hate their master Swans? Still will there stand sixteen equine Knights, in violent defense of the realm. Not even murder may keep these mares from their duty.
"But what of the coal-eyed slaves?
"What of them? They could not count themselves; they could not care unless you asked them to… why would you bother?"
Would it be fun to adventure in a place of perfect, unbreakable order?
Of course! Adventuring is fun by nature: hyperviolent pseudo-medieval tragicomedy, always fun.
Besides, the unbreakable is meant to be broken. In the semiotic slippage of communication, there is always room for error to become reward.
The agile minds of players not in actual mortal danger, become the furnaces of insane genius, wild improbable risk yielding unthinkable reward. (Failure results in dire and preposterous consequence, of course.)
The players will find that slip in your words and twist until the whole engine snaps. The murdersome vagrants will throw themselves bodily into the machine until its gears are choked in bone,
Or maybe they won't. I don't know, but I bet they'd have more fun if they did.
Watching the world you started burn by the time they finish it, is a rare and wonderful thing.
There's just nothing more D&D than busting through a wall and skipping most of an adventure. There's nothing more D&D than a botched roll killing the prince the violent fools were sent in to save.
With D&D, et al., you never know until everyone is dead or kings or Jethro can't make it to the next game.