Original	Revision
Almost everyone agrees that the state has a role to play, but there have been intense debates on how the state should act.	Almost everyone agrees that the state has a role to play, but there have been intense debates on what that role should be.

Here, repetition of role makes the contrast beween 'agreement' and 'disagreement' clearer and more pointed.

.

This shows that the resource allocation provided by the market may not be efficient, and thus provides a rationale for government intervention.

This shows that the resource allocation provided by the market may not be efficient, an inefficiency that provides a rationale for government intervention

In the original it is not exactly clear what provides a rationale for government intervention: the revision shows clearly that this is the (possible) inefficiency already mentioned.