Since late January there's been the first E18 development release and Carsten Haitzler (Rasterman) confirmed last weekend at FOSDEM 2013 about plans for the next major release and also went through the major features of E17.
The important details to share is that the developers of this alternative window manager are already working on E18, their goal is to release EFL 1.8 in April or May (the Enlightenment Foundation Libraries that make-up the desktop / window manager), and they will be trying to do "one major release per year." This means we may now see E18 officially surface before Christmas.
Enlightenment E18 will go "beyond desktop" and will look to be "one window manager to rule them all." Samsung has already backed Enlightenment for use on various non-desktop form factors and Enlightenment/EFL is hoping to make more inroads for mobile devices. E18 will also contain greater polish and more default profiles, work on minimizing the CPU and GPU usage, use less physical memory and not to cause any swapping to disk, and other ways to conserve less power usage in order to extend the battery life of systems.
For those not using GPU-based rendering, the next Enlightenment release will try to deliver on faster software rendering and to perform a-synchronous rendering and use multiple CPU threads.
Enlightenment developers are also still working on integrating support for Wayland to deliver a more efficient experience, be "close to or better than Android", and offer greater security. However, there's still a lot of work to be done for Enlightenment/EFL to be fully baked for Wayland.
Other Enlightenment features talked about in Brussels were more physics, sounds, compositing signals, an improved gadget infrastructure, and making it more easy to share wallpapers/themes/profiles for Enlightenment.
All of the slides that go over these initial Enlightenment E18 plans plus a run-through of the current Enlightenment E17 desktop can find the slides here (ODP).