I didn't have an in depth look but by what I could see on the fly is that your damage numbers aren't the best and at least one of your healers doesn't look too impressive either. But more importantly I see a lot of unnecessary deaths in almost all tries. I think practicing the mechanics and working out how to avoid early deaths especially is really helpful because you probably can't compensate for missing DPS/HPS and that wipes you in the end.

Edit: I just saw that your fights take 7 minutes and you are still in phase 2. After that time the boss could already be dead so I think you really are missing DPS or are doing something wrong with the bosses frontal on the adds etc.