Well first of all you don't mention Forgemaster's, in D-mod it's a massive heal. Also, in my experience, Astral Seal seems to heal quite a lot if you tag all mobs before you hit 'em with your AoE. I'm also using the at-will DoT (Brand of the Sun), by taggin mobs with that and A-seal you get passive healing while still…
Im by no means a so called "pro" player, but I realized quite early in my DC career, that my survivability sucked. I that led me to stacking defence and that actually helped me a lot, my spec and my gear are both focused on defence and damage resistance so I'm quite a tank. That also helps in skirmish and dungeon PUG's…