You've logged out as fury.
Taunt swapping requires teamwork, Paladins are little farther ahead of warriors and DKs when it comes to DPS (hopefully will be rectified with Riposte and changes to how taunt works in 5.4) so the issue requires a little better control from them when tanking with other plate tank; the other tank has to lift off on threat. For most tanks this means stopping or at least slowing DPS, for pallies they can just Hand of Salvation themselves and carry on trucking.
Use your CDs on the taunt swap. You're a prot warrior care about lust alsmost as much as you care about spirit and you really shouldn't be in the pool whilst tanking anyway you could dip a toe on as you taunt for a little extra burst. Take Glyph of Heavy Repercussions over Glyph of Bull Rush; on a single target rapid taunt swap fight like Jin rokh, Shield Block should be up nigh 100% of the time when you have aggro, and Shield Slam should be your largest source of damage I generally get 35-45% of my total damage on single target as being shield Slam, so that glyph alone is worth 8-10% of my total damage. Consider taking Dragon Roar, it won't be available every swap but it is very good at securing threat.