I recently started tanking and have been running heroics. I usually do OK in boss fights, but I tend to have some issues in trash pulls. I think a lot of it is due to bad dps going crazy in the first 2 seconds of the pull but I'm still uncomfortable with my threat generation. I usually use DnD-IT-PS-PT-HB to start each pull. This is my armory.
I know I have to change glyphs, I just haven't been able to find the Glyph of Obliterate at a reasonable price. I bought the mats for a Titansteel Destroyer last night as I had been using the axe from the Amphitheater of Anguish questline previously and thought the boost in threat was worth the investment.
I haven't reached the hit cap nor the expertise softcap. Should I be gemming for it?
Is frost the right spec for me? With all the things I've recently read about blood I'm tempted to try it but since my biggest issue is aoe threat I thinking it's not the best spec for my needs.
Spec is ok, glyphs are as you mentioned terrible. All three glyphs are just terrible for a frost tank. Get Oblit, FS and as a 3rd I would go with HB because it applies FF to all targets it hits, eliminating the need to ever apply diseases (just don't use PS)
Also are you unsing Runestrike whenever possible, i have it bound to all main ability like this;
/cast !Rune Strike
Lastly don't gem for str, if you want more threat then gem for avoidance. Outside of that its just gear related!