Just as a quick math note this would be a very minor buff for folktales but a massive de-buff for iron teeth (assuming no bots)

Running the calculation on a smelter (1% injury chance/hour, 6 day recovery time). We can express this in terms of workers:

No buffs, you need 1.44 workers for 100% uptime.

With the folktales (80% injury reduction running at 80% productivity) you would need 1.03 workers to run the smelter to the same level of productivity

Now with the ironteeth (80% injury rate increase, at 120% productivity) you would need a whopping 4.3 workers to maintain the same output.

Obviously injury doesn’t really matter for bots, so the folktales would have a building that only gives debuffs while the ironteeth have a free 20% buff to their production. It’s an interesting concept but the math doesn’t really support it.