I am not surprised that you had already thought about that. I do not disagree with you about the concept of bonus stacking can break things. However I feel that it is all about scale. It could be that s good luck charm or such works for a month, but only negates one danger after rolling once, unless it is very very specific. Trading power of the blessing to wider applicability and vice versa.
It was great to hear your thoughts however, I see your point of view.