Redefine their role in law as suggested by about 10 gazillion business academics. There's lots of perfectly reasonable work on fixing problems with corporate governance, much of it championed (ostensibly at least) by the assorted accounting and management bodies, but not transposed into law.

The core problem is that under US law (in particular) the sole responsibility of a public corporation is to maximise shareholder returns (barely) within the law. And that shareholders will successfully litigate the living fuck out of the directors personally if they can figure out a way you haven't done that.