Haven't seen this. Only oddity we've seen on that mechanic is that someone was targeted for deletion with their own color, and end up clearing it themselves (consumed their buff, deletion didn't happen). We never saw that pre-2.0, and came to believe it couldn't happen.
I've seen that happen as well, this was a different colour. That's an intended mechanic as far as I can tell.
Are you certain of this? We rarely have both people of the same color die, but I am pretty sure that even pre-2.0 you would still get their circles, and the result was a ton of damage that would take everyone to basically 10% health or so. Which led to a wipe shortly thereafter.
Fairly certain but I'll admit I may just be confusing it with SM. Still, it means if certain members die you cannot complete the fight which seems harsh outside of NiM.
Not a tank, so I'm not quite certain why it would matter who they target...you still have to taunt them and keep them away from people tasked with keeping the shields down. But yeah, their targeting definitely seems different...our tanks are good, but I still had to keep my finger on the stun-break button just in case. We haven't had a clicker interrupted once in 2.0.
When they target members of the current color they attack separate targets and whenever a tank is in the middle one will run to him, ensuring they are in range, the other will ran at the channeller which is easily taunted away. If a healer is in the middle we have a both tanks free to pick them up when they spawn. This is preferable to random targeting of one of the healers who then ends up with 2 adds on them that can only be taunted off.