The tactics for this have been said before, I have both tanked and healed Battlelord Kreshan on many occasions and have had many wipes due to people not standing in the correct place, not killing adds or avoiding AoE, I always ask at the start of the fight 'Everyone know tactics?' Always have the tank turn the boss so their back is facing the console. Once had a tank refuse to do this as he was adamant he would be knocked off. After 3 wipes I quit, So the boss is a little more difficult to do than the previous ones yes but it is teaching you about tactics which are important for later Flashpoints and eve more so for Hard Modes and Operations.
To be fair, you do have to be careful of his KB, but you can easily turn him without the pit and KB being a real worry. And if your tank was acting like that... that's a bummer, but you all could have moved to the sides then. Kind of what happens sometimes in PUGs, you roll with it.