It does seem that all the legislative roll backs are on Obama's legacy. But this in part Obama's fault.
Obama didn't want to work with Congress [for whatever reason] to make the "Iran Nuclear Deal," DACA, and his other accomplishments laws, he decided to bypass Congress and use his pen much like Trump is doing.
Had Obama worked with Congress toward getting a two-thirds majority, he wouldn't have to worry about Trump knocking down his "legacy." He also wouldn't have to rely on Hillary getting elected to preserve his "legacy."
Trump is doing the same thing by using his pen instead of Congress to get [quick] results. As soon as a Democrat is elected President you can bet the same thing will happen to Trump.
This will become a vicious cycle which will make Congress obsolete