I think isomorphic JavaScript applications are going to replace the current frontend paradigm. Microservices are becoming more popular, so imagine an isomorphic JavaScript application as a frontend consumer of many backend microservices. Plus there are a slew of security considerations that cannot be solved with current frontend JavaScript.
For instance, how do I call a protected API without leaking the API credentials to the consumer? Currently you can do this with trusted hardware or the traditional server side rendering. An isomorphic JavaScript application can solve this problem using server side rendering without needing a separate backend.
This is precisely what we're moving towards right now. It allows us to break away from our current, sub-optimal backend server serving up all the services to an isomorphic JS app that consumes variety and spits back out results from API calls. It allows for great flexibility -- not to mention speed and consistency.
For instance, how do I call a protected API without leaking the API credentials to the consumer? Currently you can do this with trusted hardware or the traditional server side rendering. An isomorphic JavaScript application can solve this problem using server side rendering without needing a separate backend.