I for one see Dprot just as situational as DJ is.
And you know me, I am all about opening peoples eyes to other ideas. That is mostly my main goals with a lot of my posts. To get people to consider other possibilities, question their cookie cutter builds, ask themselves "Is my build actually the best?". I think a lot of people are using sub-par glyphs and talents and gear on a lot of fights simply because it is "standard" and it is what guides says. (read as: PoJ, HA, not utilizing unconventional gear, ghost iron dragonling etc)
Not saying that what I suggest often is the best either (except for maybe PoJ, makes no sense to use that talent). Though I think stuff like HA has it's uses. However I believe HA is more situational than SW.
People using the mastery trinket from Elegon for any other reason than "I want higher item level so I can epeen show off in stormwind/orgrimmar". There are very few exceptions depending on peoples gear where Elegon trinket can be viable, but in 99% of the cases it is not. Basically if your gear forces hit and expertise cap even after reforging away from them, then it can be worth it, if you somehow got hit/exp on like all your gear.
Now that was a bit off-topic...
If you are talking about tank swap fights, on fights where you have a fixate ability like Gara'Jal, you can spam taunt when the other tank is tanking to get vengeance. You can also utilize fast taunts and taunt backs if your vengeance falls low. I.e. communicate with your other tank, throw up a taunt and he instantly taunts back. Taunting a boss gives you 50% of the vengeance that the MT have.
We often utilize this on WotE, we taunt eachothers bosses during the dance with a macro. Can be abused on most fights tbh.