I don't think hit rating will help you much here.
70% of your threat comes from abilities that cannot miss. Holy Shield, HotR, SotR, JoL and consecrate. Might be just that your locks are over gearing your paladin too much. If anything, expertise should help you more. But I don't think it is worth gemming for it either.


What is your tanking rotation? is this on single target or multi target ? use AV shield on every CD, and all those abliities listed above. With righteous fury on, no way warlock can pull aggro off your paladin with same level of gears.