It's very common to jump to conclusions at the outset of a major policy statement. I fly in the US, and the Caribbean some times, and the US ATC is very good as it is.
Here's a few takeaways that I can offer. I'm not sure there are enough electrons to cover all the issues by all the stakeholders involved. Literally thousands of direct stakeholders, and of course multi-millions of minor stakeholders.
First, the big picture that is trying to be accomplished is to have a safe system at lower cost. That's the major goal of the announcement. There are of course, many challenges involved. It's a major step in the quest for a balanced budget in the US, and I have to say - everyone who uses some service thinks that service should be immune from cuts(or fees). The nation can't continue to borrow, print and spend money from the treasury.
All I know at this point is the basis for the original funding proposal contained language that GA planes would be excepted from user fees. The was to bow to the desires of AOPA and gain their endorsement. Whether it will pass the legislative edits and make it through to a vote, and then make it through the senate is very questionable.
Since it has been endorsed by the major airlines(to greater or lesser degree), there's a sense that it will support the majors to the detriment of business/cargo/GA. I am going to take a wait and see attitude, understanding that the major goal is to provide safe traffic control for less money.
One of the concerns is that GA planes which in some cases have the option to avoid ATC involvement will choose to compromise safety over cost. Flying actual IMC without a clearance, scud running, even using a different call sign(without ADS-B of course) while flying. I can see an incentive to cut safety corners if each time one calls for an IFR flight plan, the meter starts running on costs. Of course, that will be just one of the concerns from the GA side. The other part of the equation is if a privatization will actually save money over what is being done now. I have to opine that it would be hard, very hard, to be as inefficient as the FAA has been for the past 30 years. Since the strike of 1980, pretty much the entire ATC budget has gone to hell and not kept up with the times. I can find hundreds of places to save money without losing any safety right away. For dozens if not more than a hundred controlled towers, they could easily go back to uncontrolled, with no loss of safety. Big swaths of the midwest from Nov to March are virtually dead, but manned towers still operate from 0600-2000 each day, and they may handle 3 ops or 5. From a cost per op basis, there's no reason to have a controller sitting there watching Angry Birds on his phone, just waiting for a Piper or Cessna to show up.