I don't see how the first rule is a major design flaw. The second rule is mildly annoying but all it means is that dyn compatible traits must use dyn compatibl

I don't see how the first rule is a major design flaw. The second rule is mildly annoying but all it means is that dyn compatible traits must use dyn compatible traits in their function signatures so you have to duplicate it for the compile time dispatch and the runtime dispatch.