yes and no
EM doesn't have as much dmg mitigation as some of the other sets
EM doesn't have a ST dps chain that's so much greater than other sets that it makes up for the relative deficit of dmg mitigation
If you're against one mob or even two or three mobs it works well enough. However, after that it really loses its luster when compared to other sets.
For soloing small spawn mishes em may work well enough, but it may not work as well for other things or even as well as other sets.
It's not more common anymore because most CoX stuff revolves around team situations or larger spawn size. Many soloists are enhancement farming which requires more AoE capacity. Merit farmers like Stalkers for their more easily achieved burst damage and inherent stealthiness
Energy Melee had a recent nerf. Or at least, that's what a few of us like to call it. Basically, the animation times were increased, and that really hurt the single-target DPS of that set. Now, dark melee is king for single target DPS.
Energy Aura is an unusual set, partly because it's a twisted version of ice armor (gimme ice armor). It has a significant psi hole, which makes it less preferable to the positional defense sets like SR and SD. Now, EA isn't a terrible set, but I have yet to be satisfied with any EA build I've done. I've wanted to like EA, but I just can't.
What it needs is a way to fix that psi hole and a better power choice than conserve power. Energy Drain is plenty.
Energy Melee / Energy Aura Please explain, how come this is not a more commonly used set, seems great ST damage, so it would probably be good for most soloing activities or even AVs correct?