General Question

[Jpec07]

Is there a reason a lot of tanks are still trying to tank in dps stance and causing consistent wipes?

Because just about every guide out there for 3.0-3.15 promotes using tank stance (i.e. Deliverance, Shield Oath, Grit) as a cooldown that's only necessary for periods of heavy damage, and during that time, tanks could largely get away with it (my FC healers would often vent in /fc about how much they hated it, but that's a different story). Now that they've nerfed tank damage in general (and thus, enmity generation outside of tank stance), tanks who learned how to operate this way are encountering a culture shock, and are likely refusing to stay in their tank stances because of the mountains of rhetoric arguing against it.

That, and they probably didn't read and interpret the patch notes.