Related: E16 version announcement for release - #2 by Thanatermesis
Well! thats a good question
In fact it is, but e17 (or newer) is SO light that can be easly comparable, the difference is that newer E's can require bigger resources easily (like using a theme which requires more, for example if in your elive stable you switch between the elive theme and default dark theme you can see that consumes less), even the wallpaper creates a noticeable difference
Yes, 64 & 32 bits are differently optimized, but has not much relation with the desktop... I mean, yes e16 can be lighter but its an entirely different experience (which has a bigger impact), so its sounds more like "elive flavours" related to the desktop than related to optimization
By other side a super light version could be made too, but this will meant to remove a lot of features (cairo-dock should be not included probably too, well, it manages the ram pretty good but it adds between 50 and 150 mb of extra ram required to run it... but removing it, much less features)
Good point 
I will add this sentence to the other thread in order to collect some words / ideas
