The radicals in the Republican Party are morphing the non-partisan civil service into something that more and more resembles the spoils system. This is one of those below-the-radar changes likely to have massive if obscure effects.
The political spoils system has some virtues. It makes accountability clear: no bureaucrats to blame if you can hire and fire them. It may make the bureaucracy more efficient, in that it makes firing the incompetent easier. To the extent that salaries are flexible, it may make hiring and retaining good people easier. The thought of government jobs may encourage more people to work in politics (I think that's a good; some might call it a bad).
Of course, political hiring and firing has substantial disadvantages too. Good people may be less willing to work in government if they know that they can be fired by an incoming administration even if they're doing a great job. It encourages featherbedding. Bad people with good political connections can stay in office where in a more merit-based system they might not. Whistle-blowers become an even more threatened species. Generally, politicizing the civil service means rapid turnover when administrations change. That tends to be bad for the quality of government administration: institutional memories are lost, wheels are reinvented, dumb things happen.
Although the Hatch Act of 1887 has been modified at the higher levels by the creation of the Senior Executive Service to permit political appointees somewhat more leeway as to who their top civil servants are, the basic idea of a non-spoils, non-political federal bureaucracy has been the American way for generations. There are also some Supreme Court cases holding political firing of lower-level employees unconstitutional, although I've always had my doubts about the correctness of those decisions.
This week's changes don't completely undermine the Hatch Act. They don't make straightforward political hiring legal, but they remove some (but not all) of the existing obstacles to political firing and pay cuts (and pay increases) for about half the civilian workers in government. They'll probably lessen the power of government unions.
Unless there's some sort of immediate institutional bloodletting, which I think highly unlikely, it may take years to see the full effects of this one, be it good or ill.