#1 hit is not really important for a tank, the only important point is taunting and therefor you can use the glyph http://www.wowhead.com/item=43429 which give you 8% hit for taunting. I personally like a little bit more hit, but you need only around 100 hit rating, that shout be enought. I use http://www.wowhead.com/item=44497 on my tanking weapon, that give you an extra hit :-)
#2 Expertise is the most important threat stat for tanks. If you have no threat issuses, you can run with 19 expertise or something, but if you struggle get more exp to get softcap or even higher.
#3 Both trinkets are very strong. On a hard hitting boss i will prefer Black Heart to give your heals a little bit more space to work with. On fast hitting bosses or if your heal are comfortable with healing you, i will take the glyph. Or at a boss fight, where you need a timed cooldown to avoid damage. The procc form Blach Heart are really strong, but it's a procc and in worth case not up, if you need it.