Flanking has always annoyed me. Let's not talk about skill floor here please. Oftentimes it's impossible to determine where the boss's head or eyes are, either because it's an ehm very unique creature, or because it does a long spinning attack. Also there are times when you have to stack on people that don't flank or god forgive tank something yourself. It's not a fun mechanic, it never was.

I think over time they'll probably rework the existing flanking traits as well.

edit: I don't agree with the argument that you HAVE TO do something for that 15% extra damage. Pve game balancing always assumed you were flanking 100% of the time anyway, since it was always factored in, might as well make it real too.