You can´t keep SB up all the time in m+.
Most of the time you are tanking trash. You collect mobs, you have to look for aggro and abilities to stun/interrupt. YOu might press SB 1 or 2 times per pack but that´s it.
No need for HR.
Even with tyrannical.
The fight are simply not long enough and there is always something happening where you can´t use SB all the time.
At least, that is my opinion.