My impression about Gutenberg: too fast, too early

Unless we don't have an option to set the old interface at least for a custom post type (but it would be better on a post basis) I can only see thousands of plugins broken and never fixed and thousands of sites left without a working plugin that they have used maybe for years without issues.

The WooCommerce team has not yet figured out how to adapt their complex interface to the new paradigm. If a branch of Automattic itself is having hard time with Gutenberg I can't even imagine teams of one or two people. According to Matt WP 5.0 will be out early 2018, so we are weeks away from having the new editor forced into WordPress. If the old editor will be available only as a plugin and not as an option the whole ecosystem risks an implosion. Thousands or even millions of websites made unusable with the new update, thousands of old free plugins vital to these sites will be broken and never fixed.

There are free plugins in the WP directory that have been built and have evolved slowly over the years. They've been built by the authors in their free time and over years of time, and you cannot possibly force them to update the interface in a matter of weeks.