Over the years, federalism first changed to give the national government more power. Since the 1980s, things have swung back towards the states a little bit, but I do not really buy the idea that there has been serious devolution.
The federal government has taken more and more power over time. This happens especially in times of crisis like WWII and the Great Depression. For the most part, the power never goes back to the states.
President Reagan talked about devolution, but it was also during his time that the federal government forced the states to change their drinking age to 21. The Republicans talk about devolution today at times, but it was President Bush who was behind the No Child Left Behind law that caused more federal involvement in schools.
Would devolution be a good thing? It depends on the specific policy issue, I think. I think that some things need to be on the federal level -- things like basic rights and like welfare policy (so states don't have a "race to the bottom.") But on other things, like perhaps health care, it seems like it might be good to have devolution so different states can try different solutions.