If that happened it would indirectly change the incentives anyway, because everyone would start being required to release data, so bad practices that are currently incentivized would become impossible.
However I think it would be better to directly incentivize data release rather than require it, at least in biomedical sciences. Because of patient privacy issues there is no way raw data release can be required across the board. And I certainly do not trust the NIH to come up with a coherent set of rules for when it is versus isn't allowed, which would mean loopholes and more corruption.
Most projects are funded by a patchwork of different sources, not all of which would agree to the same terms of release of the information, but all of which are required sufficiently fund its creation. Not to mention maintaining ongoing storage and accessibility. single source government grants for scientific research are the exception, not the rule.
However I think it would be better to directly incentivize data release rather than require it, at least in biomedical sciences. Because of patient privacy issues there is no way raw data release can be required across the board. And I certainly do not trust the NIH to come up with a coherent set of rules for when it is versus isn't allowed, which would mean loopholes and more corruption.