@Saram:
I prefer FS/IT/DnD glyph's.
DnD is going to be used often because you are tanking more trash per run than bosses.
Obliterate dmg does not add up...it may look like it's better than HB because you are using it 2 times every rotation and excluding HB completely other than Rime procs...so yes, doing it that way would make HB look terrible. You are also going out of your way to make Obliterate good...whereas HB is good alone...without that sigil and glyph IT will crit just as often as Obliterate...costs 1 rune instead of 2...and does almost the same damage as an unglyph'd/sigil'd Obliterate...all the while generating the same amount of RP for half the rune cost and allowing more chances for Rime to proc which will in turn free up the use of an Obliterate.
With your rotation you are spending KM procs on IT or FS...both of which do less dmg than HB.
To use Obliterate Sigil means giving up SotUK which means losing avoidance to gain tps that isn't really needed...the 11def skill from sigil is .44% to dodge/parry/miss or 1.32% combined avoidance (before DR).
Saying the tps from HB is erratic due to hit cap doesn't help your argument either...Unless you are expertise capped for Dodge and Parry your Obliterate has a higher chance of causing no threat than HB does...with buffs/debuffs it's easy for a tank to hit a 12% or so hit rate on spells (without virulence) leaving a 5% miss chance compared to Obliterate's dodge/parry/block chance which is much much higher, causing more erratic tps than HB.
Relying on KM for HB procs is still a non-issue...I would rather have a guaranteed crit, that requires far less gear, than a RNG based crit that requires several pieces of non-tank oriented gear.
If your tps is enough to overcome your dps'ers threat then the next logical step is to increase your survivability by any means...not taking an avoidance sigil is a mistake imo.
By the same token of swapping gear/glyph's to improve an ability...why not swap trinkets for Mirror instead of spending wasted points...or use some dps rings...you wouldn't do those things because you would be losing valuable tanking stats...well you're losing valuable tanking stats by not using the sigil..and losing higher AE tps by not using DnD.