Looking over the Deaths over view for he first couple of tries, Galook seems to be being munched by both bone warriors as Onyxia. Firstly thats a crap ton of damage, Onyxia hits hard enough as is, and Shadow Flame Breaths just gonna keep the adds up indefinetly, making them hit for a crap ton. Your onyxia tank shouldn't really be tanking adds.
I'll keep posting/editing as i peruse later attempts
Edit: try 4 Galook got one 3.2k heal over 11 seconds
Try 5 somone failed at interupts
Try 6 Ony tank didn't pop a CD for Electrocute, but also isn't getting much healing apart from his own
Try 7 your DPS add tanking got caught in ony lighting discharge, either his, or ony positioning was at fault, the adds munched a healer P2 making phse 2 impossible, I assume the priest realised this and didn't jump up a platform.
Try 8 DPS shaman fails at getting to a pillar everyone else seemed to die through insufficient healing assumed a wipe was called
Try 9 looks like the rogue wasn't fast enough getting on to a pillar and then someone missed an interupt (the rogue coz he was late getting to a pillar?) DPS shammie is also in the lava for some reason
Try 10, Rogue seems to be really badly positioned, and someone(s) failed at interupts
Try 11 people are standing in the pink fire
Try 12, rogue fails at getting onto a pillar, the addtank gets bugger all heals
try 13 Nef tank only get heals via Beacon.
try 14 someone(s) fails at interupts
try 15 Adds on healers in p3, people standing infront of the dragon,
try 16 Priest fails at getting on a pillar, Interupts failed again
try 17 Priest is hit by onyxia's discharge, not topped off before an electrocute
try 18 someone fails at interupts.
Edit 2: Rogue's not using Feint anywhere near enough, it's works against electrocute, so he should be having it up for each one, in phase 2 he should be aiming for maximum uptime. Looking at the longer fights there's not alot of defensive CDs being used for them, The warrior never used Rallying Cry, No shaman bothered with Glyph of Stone Claw, the locks not making the most of Nether Ward, only 6 people are using their healthstones. I would assume (and this is tenuous) but becuase your raid are not making the most of their defensive abilties, the healers are struggling and that wahy tanks are falling over. or it could jsut be that the healers are struggling any how. The interupts seem to be not managed well in phase 2. A few mistakes are creeping in.