You have no clue about enmity mechanics obviously. A RNG doing his job (DD) would have to gimp his abilities substantially to keep a mob from ever going after him. That's even with max enmity gear and Coronach. Until SE fixes the enmity formulas (fat chance) maxing CE is only a matter of a brief amount of time. Add in all the hate reset moves these new NM's have and most fights degenerate into whoever hit the mob last gets hate.
Basically, much like BLM's, ranged attackers have to gimp themselves to avoid getting into AoE range. I've been double weak many times on RNG and COR largely because with single weakness you can outperform other weak DD's and are soon pulling the NM your way for a one shot kill.
That being said I can live with this mechanic as annoying as it is. I'd rather Se worked on enmity generation for ranged attackers to lessen the chance of being double weak in the first place.