"...releasing a cover without permission...is not ok."

I have to disagree with this. And it's already allowed with Compulsory Licensing. The writer of the song gets their cut as specified in the law.

As to the rest of your comment, I don't think you mean "broad protection." Broad protection is exactly what allows 'silly' lawsuits. Something that's "too similar" gets into trouble because the protection for the original is too broad.

Now, making a transformative work based on others is where I feel things get interesting and there should be lots of flexibility and leeway for the transforming artist. But how that could possibly be codified into law I have no idea...