You can also take withdrawals from your 401K before 59 1/2 if you retire anytime in the year you turn 55.
Back on the OP, though I still haven't seen documented language of exactly the Rs wanted to do, I caught some talk on the radio this morning that suggested they actually wanted to keep the 401K amounts the same, but just make only the first $2400 pre-tax, and do the Roth thing for the remainder.
While I still wouldn't have liked that for me personally while I was working, that would be a hell of a lot better than ONLY $2400. If this is true, while I normally default to blaming the MSM for fake news on the subject, this still seems to fall directly into the laps of the Rs as incredibly bad PR on that part of their plan. The lead should have been some spin on how they would apply Roth rules to 401Ks, with a big, bolded headline about how the amounts weren't going to be messed with. Just terrible execution on the public perception and information side.