To quote myself and probably a dozen other people DPS covers a multitude of sins. So does a ton of healing, so does an off-the-charts tank etc etc etc. You have to work with what you have and build on it from there. Maybe seeing what you can squeak out extra in DPS from your crew is the place to focus. Another couple procs (augs or dragonmagic potions) or finishing synergy, upgrading dissident or even tribute and trophies is sometimes enough to make the difference in out of mana and wiping versus sucking fumes at the end but you get the win. This is certainly the easiest way to do it and the fastest but by no means the only way to win. If you're not trying for or are struggling to get the Unrushed achievement I'd save my burns for the 2nd guy (Icebound Bledrek). The gargoyle is relatively low hitpoints and doesn't spawn any adds so you can take your time. The 2nd guy is the one with all the hitpoints and he's the one that is going to be generating most of the adds. The hay/snot/mud whatever you want to call it ground spawn is key and you just need to be looking for it. We fight the gargoyle where he stands when you start the mission, then we fight the golems where they stand. You have a good 3-4 ticks to get from the dead gargoyle and get setup on top of the golem before he goes live. (just don't fall down the stairs) If you're in the little hallway that the golem backs up to you can use just about any spot in that room to place the clicky and they path around that room long enough trying to get to you to buy time. You can also punt them into the pit if you have a shaman but I haven't heard you mention one. All the fleshpile adds are rootable, just don't hurt them because they summon.
It is doable by a well played Bst. The trick is to use the pet to tank the boss and build aggro then turn pet attack off so that he doesn't over damage. You then need to learn the spawn % of the adds. BTW if you go very slow you only have 1 add up at a time. The problem is people tend to DPS until they see the spawn and by that time you may have trigger more then 1 add. When you know the spawn % you can trigger a spawn then wait and you will never have more then 1 up at a time. This works on both the lower level and upper level. It can be done but it is Very Very Very slow. Also merc do not duck but also do not die so Merc will heal just fine and a bst can help heal the pet/ rune the pet.
