If a tank loses aggro, whose fault is it?

[Venoshock]

I'm curious, is the new tank meta not to use defense stance so they can push out a little more dps?

Yes but they Should rotate their cool dows to compensate for the lack of stance. Nothing in this game outside tankbusters and large pulls hits hard enough to warrant 100% tank stance usage.

Think of it like healers using their dps skills, they do it because again nothing in this game outside pvp requires them to be in healing mode 24/7.