I'm 0/6 on KC which isn't nearly as bad as some people!
Easy BCNM, RDM BLM BLM, although it does tend to start to resist sleeps eventually and I had a particularly bad run where it outright resisted many sleeps in a row and had to be kited/bound while blms rested. Ughx2
Assuming what FailureMidgard said is correct and they don't rage cause of magic (which I disagree with btw), the way I see this being done with 3-4 is:
BLM to nuke-kite-kill the whm queen at the start of the bc, so it won't cure the other mobs.
NIN/DRK to solo the blm queen (might be immune to stun, not sure)
PLD/NIN to kite the king while the queens are being killed
RDM/WHM to cure the NIN/DRK.
or
BLM to nuke-kite-kill the whm queen at the start of the bc, so it won't cure the other mobs.
BLMx2 to nuke-kite-kill the blm queen
PLD/NIN to kite the king.
One thing to note is that, when I did it, the cardians never raged on us. Rather they 2houred, we took too long or whatever. We didn't cast a single magic spell (elegy was used) on the cardians throughout the BC. Party was pld, war, war, rdm/nin, whm, brd 2boxed.
Your pld was sub war and managed to hold hate never using flash? Or did you kill both queens before the king and the pld just kited at the start then did nothing after?
I'm curious as to your exact strategy. Also, there are a ton of factors that aren't even being discussed as to what causes the rage (King before a queen. Different Kings could even have different rage mechanics).
PLD was /NIN and kited the King. RDM kited the WHM queen. Melee kill the BLM then the King then the WHM queen.
PLD kept hate by curing the melees but the cardians kept on resetting hate on the PLD so it would turn to the melees alot. And like I mention, all the cardians have en-spells so I think PLD/WAR would run into alot of problems.
Did royal ramble many times and always used this setup: 3melee/nin, rdm/nin, whm/blm, rdm/blm. The best setup would be to replace the rdm/blm with a brd but then the whm would have to escape and run back 5 times (hate balga's dais).
Main strategy is the rdm/nin will cast a weak spell (stone) on the king first and one of the melee voke it off the rdm. This will cause both queens to aggro the rdm/nin while the rest finishes off the king. The rdm/nin can hold the 2 queens easily since they never move to melee range. Stoneskin and magic defense bonus makes the rdm survive the occasional GAs easily.
Once the king is dead move on to blm>whm. Always finished the fight in about 5 mins.