Endgame Tanking and hit rating

[Candyfloss]

What does hit really do and how important is it to end game raiding? I'm a decent player and know my part I'm just not very smart when it comes to talent spec... I play for fun and do my job. my armory link is here
The World of Warcraft Armory (http://www.wowarmory.com/character-sheet.xml?r=Skullcrusher&n=Zilltoid)

I compared myself to ciderhelm and noticed our stats are very similar except he has 108 hit or something and like 4k more health... I know alliance get that heroic presence from drenai but does that stack? O.o why can't I only ahve 108 hit and be good :(

[Synapse]

Hit helps you...hit stuff. This means, primarily, that your debuffs are more reliable to keep up(demoralizing shout, thunder clap, sundervastate), and your taunts will be more reliable too.
If the attack is parriable/dodgable, then you add expertise to the same effects of hit.