1) I'm confuse, you take Defiance OFF but let a Savage blade go through o.O....I'm sorry to tell u this but a warrior should NEVER have savage blade. You need Provoke, Flash (Saves TP from OP/lower dungeons, Convalescene). this are the cross-class skills from gladiator.
2) You cannot take aggro from other Main Tank, unless u have a) Defiance on, b) Spamming Butcher block combo, even than is hard to take off unless u are using DPS accessory/MT not using aggro combo. U should be rotating b/w S/E or S/P and BB
3. If you are MT on boss and trash adds spawn u NEED* to pick up trash adds (unless dps is high to burn adds quick/overgear pt). you will not loose aggro on boss as your enemity should be high by time adds spawn.
4. put that flash/provoke back on your skill bar
5. if you are OT, take defiance off/ put it back on when about to tank swap/adds spawn, if someone else tell u to put on while u OT,tell them to stfu*
6. warrior is best for AOE so u should not have issue with aggro, when u pull, let adds gather up and do 2 OP than began combo other adds, if mark target start there if not mark, look at the enmity list, and combo that one that starts to loose hp fast. rotate Enmity combo with different trash adds. (example heavy swing main trash/skull sunder, switch target and Butcher blocker another target)