1. In your scenario, you say you killed a healer with Fester, Enkindle, and Energy Drain. I'm going to assume you mean killed them with the burst damage of those actions altogether, meaning you used Garuda. Garuda's Enkindle Potency is 250. That is less powerful than the max damage Fester you miraculously managed to pull off, meaning all your dots were also applied and doing massive damage. Enkindle was just icing on the cake. I dare say that healer would have been screwed if you had just used Fester, Ruin II, and Energy Drain, not to mention Garuda's additional DPS and cast interuption.

2. Let us not remove Resurrection from Summoners and have a DPS or Tank kick the crap out of any rezzed player. That could work, too.

3. Keep Energy Drain the way it is, it's tied to Aetherflow, meaning that you can only use it 3 times in a minute.