You may have already read Matt Mullenweg’s blog post outlining the decision to take React off the table for inclusion with WordPress core and related large-scale projects like Gutenberg.
This is one of the bigger decisions in our space for quite some time, and it’ll be a while before we work our way through everything involved — primarily choosing a framework to use. Preact is high on a lot of lists but Vue is in the mix for sure too. I have more on this, but for now, read Matt’s post.
This was likely not an easy decision, but I think it was probably the right call.