Armory Lookups, most likely should be in HALP !! Forums, Kaze will move it if needed.
I would not worry much about hit as a tank and totally not about crit. In most cases if a tank is loosing aggro its either the dps being way way over geared than the tank (and trigger happy) or tank not using the proper priorities for threat generation. This thread may help http://www.tankspot.com/forums/f14/4...-rotation.html
Hmm tons and tons of upgrades/improvments etc etc possible. Rather than listing them all I will just link you a post which is stickied on the top of forums where you posted
Get the right enchants (like dps enhcant on helm o_O) you will have no issues with keeping defense at 540 and than gem for stamina wherever you can. You might be able to fit in the 32 stamina meta gem