I'm not sure why so many people are freaking out.

Looking at the changelog, it looks like they decided to commit a bunch of breaking changes that were previously marked as deprecated. If your code was running before without warnings, upgrading shouldn't have a negative impact.

The pace of change is fast because node ES6 support is progressing fast enough to maintain near 1:1 feature parity with v8. A bunch of ES6 features still haven't been fully implemented in v8 but that's not the fault of the Node.js dev team.

If the dev team has committed to LTS for 4.2 that means they're likely planning to backport new features to the 4x branch. No reason to panic. Many of the more useful features of ES6 already work perfectly in 4.2.