Fester shouldn't be totally disregarded I believe. Even with 2 DoTs of 200 potency the ability to chain Fester > Ruin 2 > Energy Drain is still devastating in itself. Energy Drain has a 3s CD given it is not far apart still it can tighten the burst time frame. I'd give anything to have more off GCD damage in a shorter span of execute time. For starters, if say BLM were to get all their procs instantly used/off GCD I'm sure they get QQ-ed at too.