While Preact, a lightweight React alternative with the same API, would be the obvious replacement, a majority of the community prefers a switch to Vue.js. An opinion I highly support. I had the opportunity to learn and work with Vue.js in my day job and for shortfil.ms 2.0 in the last couple of months and I’m hooked. I think it’s right up WordPress‘ alley, because it’s an easy to learn, yet powerful framework and could be a perfectly fitting foundation for modern front-end development with WordPress in the years to come.
TL;DR: +1 for Vue.js