Ignoring the point that the frameworks we already use are major abstractions on top of abstractions, if this new "abstraction" truly eliminates the complexities of client-server-client it will greatly benefit developers and users alike.
A good many (most?) of the bugs and performance problems (and security lapses) in today's complex webapps is due to the complexities of managing this client-server divide. Even when the developer does things right according to docs and examples, it's possible to end up with a system which does not perform well without solid understanding of what's happening in at the endpoints and in the middle and clever optimizations to solve the special needs.