I agree on Cat glyphs with you. As for Bear, I do get to MT a lot, and like [Glyph of Frenzied Regeneration][Glyph of Growl] [Glyph of Rebirth]for raiding. Even if you never had a resist, you just would not want one in certain situations. I guess its got to do a little with playstyle as well.

With the New Glyphs for Druids I find that [Glyph of Survival Instincts] , [Glyph of Growl] , and [Glyph of Frenzied Regeneration]. To be the 3 best MT glyphs, unless you are trying to still be the OT role of a Feral Druid or you have enough +hit rating to sub out the Glyph of growl, it would be a good idea in my opinion to pick these up.

I wouldnt leave glyph of Maul out. It helps a lot on trash, it is also useful on bosses like Hodir (dmg from maul and swipe helps breaking frozen flesh) or Thorim (trash part of the boss encounter).

I considered glyph of growl as totally useless (i never missed a taunt over last year that would be critical and would be hit if i used the glyph), but in Ulduar at least on Thorim i got taunt resist twice yesterday which is quite a lot (compared to 2 resists on Brutallus over half a year). And its basically the same situation, tank can die any second with the debuff. So for this fight i'll reglyph Growl for this particular fight (since you can change glyphs anywhere now, its best to adjust them to the fight's needs).

The usefulness of [Item not found!] would somehow differ, depending on how much hit you happen to have on your tanking set.
Hodir is a nice example where it would be very useful (wearing the frost resistance set and a resist would endanger the non-frost tank).

If you mostly MT, then you wouldn't have much opportunity to use that rebirth glyph. It might be better as another one? Could see that being useful if you were something other than an MT.

Remember that you can swap glyphs anywhere now. I carry a bunch of [Glyph of Growl] and [Glyph of Maul], and I just use whichever is appropriate for the particular fight. I haven't felt [Glyph of Rebirth] is worth more then either of those, though there may be times when it's more useful then [Glyph of Frenzied Regeneration], so maybe I'll start carrying that as well.

I recently discovered the glyph of savage roar so I'm using that one together with, rip and shred when I'm in catform. Last time I raided I had a manglebot in the group so it was neat. But I'm thinking of other times when that may not be the case, and I have to put up mangle by my self, without the mangle glyph it feels that I have to press mangle all the time, almost I'm wondering if anyone knows how big the dps loss would be if I would exchange the savage roar glyph with glyph of mangle. If its not that much loss I may go with the mangle instead just because of convenience.

A bit offtopic: I dont know about hard modes, but on normal 25man mode i solo-tanked hodir without any problems. I used polar set, cloak and head FR enchant and FR ring. 530 resistance and 52k hp buffed, and no threat issues (i did berserk at the start and on every CD).

The last simulations by nightcrowler showed:

The numbers may or may not be a bit off as i'm not sure when this was updated the last time, but you should be able to get the proportions. Or maybe Nightcrowler takes the time to answer you question

Taken from: FeralbyNight (Cat & Bear simulation tool)

I've considered using [Glyph of Barkskin] to facilitate battle ressing while tanking. The idea was that you would be slightly less squishy with Barkskin up casting a Revive in caster form, with this Glyph, due to the lowered chance to be crit.

But testing it out, it just didn't help a lot, the incoming damage was too high even without crits, and most bosses have at least a 3 second period that during which you can battle res or Innervate.

That, and it's hard to beat Maul/Growl/Frenzied regeneration for all around usefulness. I am eager to try out [Glyph of Survival Instincts] on phase 1 of Mimiron, to absorb Plasma Blast.

SotF is active in all forms. How would [Glyph of Barkskin] help when battle ressing?

A novel idea! However as you discovered not particularly useful in practice. As a side note: I once combat ressed a healer in between melee swings while tanking Sarth in a Sarth 3D 10 man