Yes, it seems very unconservative to ram through radical changes in the tax law. I guess that they don't believe in letting people adjust to any of the changes by phasing them in. The only way to be safe is to save every penny that can since you never know when they're going to change all the rules in Washington. That's especially the case judging by the following graph of the federal debt:
You can find the numbers at this link. As you can see, at 106 percent of GDP, the gross debt is much higher than it was during Reagan's 1986 tax reform (46.7% of GDP) or even Bush's 2001 tax cut (54.6% of GDP). Now we're tacking on another $1 trillion of debt according to the latest JCT report, even under dynamic scoring. All just in time for the Boomer retirement, nine years into an expansion when we have historically had recessions every 10 years or so. But maybe this time it's different.