When i ran this build on my bm, i had crit chance of about 80-90% and my entangle finally felt powerful once it hit over 250k tooltip dps and extremely strong once it hit 700k. 48% crit and 66k dps is a little low for endgame imho.
You need both high crit chance and high dps for coc to trigger often since the energy to trigger it is only gained from critical hits and it's a percentage of the damage dealt. It is also hit dependent because every hit is a potential crit and thus energy generator. High hp mobs and high mob density give you lots of comets if you have the dos to sustain, few weak mobs wont generate as many if any cause they just die too fast ti generate enough.
For this build to really come online, you want to get the entangle up to like level 35+ and over 300k dps and the comets will come.