Your analysis sounds pretty convincing overall. I will only address one specific point:
andorblue1 hat geschrieben:losing willpower is not that bad, and reaching '0' strength doesn't kill the heroes (?), so you can even stay at low willpower without risk
Some heroes like Bragor and especially Drukil are really dependent on willpower points – they might spice up the difficulty of this legend.
While the heroes usually don't die from falling to "0" strength points, I seem to recall there being a rule along the lines of "losing a strength point when you only have one left results in the hero being knocked out and unable to perform any actions or "freie Handlungsmöglichkeiten" ("free action opportunities"?) for the rest of the day".
But I don't remember whether this rule is official or optional.
Best Wishes
The butterbread-bear (? )