Isomorphic frameworks are a bad idea. I'm convinced that any attempt at making a single general-purpose web application framework will fail. I've seen it happen too many times before.
SocketStream, Derby, and even MeteorJS which had massive funding and marketing just couldn't do it. NextJS is just the next generation of fools who didn't research the market... Surely we can at least wait for NextJS to go belly up before launching yet another project that's going to waste several more lifetimes of human effort.
There was nothing wrong with the implementation of the MeteorJS project by the way... The problem was the idea itself. All the marketing and funding it received only served to delay its inevitable demise.