Enlightenment up to e16 always was light weight. There was eye candy that could be enabled like transparent/wobbly windows and whatnot, which could drag down a weak system, along with the ability to add high resolution wallpaper that took up a lot of memory, etc, but the core of the window manager doesn't have any kind of bloat or slowness. It was always configurable to be snappy and low resource. Just like fvwm.