I agree it has become a pita. I think they are recharging their sheilds faster, and either have more HP or are hitting harder. I had to make some changes, because the jousting had become a continous fail of epic proportion.

Now just before I pull the last group of adds I spread my followers out just slightly so they are still very close, shoulder to shoulder close, but not stacked on top of each other. I move my leader just behind my group. This way each of the bosses will select a different team member to attack and not gang up on one guy. And the bosses will not attack my leader at all.
My guys are still close enough that I can focus ranged and melee on one boss.

If the target has it shield up I back my leader out to ranged to get the shield down. some times a boss dies away from the pack due to range fire. Then I run the leader over and stand on the guy.

I rotate the pack to face the target boss. With this method I lose one guy most times but I am not wiping anymore.