Also the best thing to do is to do the Operator fight with 5 healers, so let one of your dps respec to heal for that fight. Damage in phase 2 is just plain BRUTAL.
I never cleared this boss in 16-man - always something caused a wipe at low HP, but AOE damage to the group is really brutal I must agree. The DPS seems to be much less of an issue. Usually we had 1-2 DPS assigned to adds constantly and cores were still going down in like 10-15 seconds each. I am inclined to think one could even bring 6 healers to brute force through this
I'll try to convince whoever is leading next 16-man TFB HM I join to bring more heals
(my guild doesn't like 16-man much so I do 16-man mostly in PUGs).