That's the spec I'm thinking about switching to. So far I think it looks solid, however I am still level 70 (right now I'm specced into Imp Revenge because it's boss for soloing, gonna respec at 80).
This toon is mainly just gonna be farming heroics (more frosts = more saronites) and maybe the occasional ToC 10 or something, no hardcore progression raiding. Mainly I'm looking for the best AoE threat spec (hence 3/3 Focused Rage and 5/5 Shield Spec for more rage for cleaves, and also Glyph of Cleaving) that still has pretty good single-target threat and of course survivability.
My main question is the third glyph slot - Cleaving and Devastate seem pretty important for threat, but I'm not sure what I should use for the third one. I'm thinking Blocking for bigger Shield Slams and Damage Shield procs (the block value isn't bad for tanking heroics or adds either). I can't imagine myself needing to pop Shield Wall every 2 mins for the content I plan on tanking, so that glyph is out.
Next question - what speed weapon is preferable? Obviously once you get decently geared there is little available to you but fast weapons, but for a low level or fresh 80 tank, should I aim for fast or slow? Slow weapon gives you bigger Devastates, but fast weapon gives you more Heroic Strikes and Cleaves, so I'm not entirely sure. (I might wind up using a DPS mace to start out just to help with threat - mace because I'm a silly dorf)