just as I predicted
There you would be wrong again, several of these attempts were made by veteran raiders who know what to do.
in full campaign/black hole with a columni geared healer.
The issue time and time again was that the healer was not capable of generating the required number to heal through the encounter. The execution was there, the numbers simply could not be attained with the gear.
Sorry to say this but then the players must have been bad, over 60% of the damage on bossfights can be avoided, I guess you veteran raiders didn't and thus put a heavy pressure on the healer and thus you failed. As I wrote above, I have done it with a tionese geared group (from healer, to DPS, to tank) and we had no major problem with any of the bosses and didn't wipe in the entire flashpoint. It's all about skill and avoiding all damage possible, if you do that, the flashpoint will be very easy.