Don't take hit/expertise. It would be like having a pain in your arm and cutting off your leg to deal with it. It won't do anything to help your arm, and it would certainly make it more difficult to walk. Similarly, reforging to expertise won't help you at all on AoE threat, but it'll sure make you less survivable.
Work on establishing threat instead. Put up a raid mark (skull) on your first target, Charge>Rend/Cleave>TClap>Shockwave/Cleave>Shield Slam>TClap/Cleave, etc. always keeping Thunderclap, Shockwave, Revenge, and Cleave on cooldown. Put most of your emphasis on the skull, but occasionally tab through to slap a shield slam or a revenge, or a devastate on the other mobs. The mobs should stick to you. If they don't, it's probably more a question of dumb AoE than a problem with you.
And stop suggesting that Warrior AoE threat generation isn't good. I usually end up with most of the mobs when my deathknight offtank and I both work on AoE pulls together. Warrior AoE threat is quite good.
Kathy, I said, "I'm lost" though I knew she was sleeping
I'm empty and aching and I don't know why
Counting the cars on the New Jersey Turnpike
They've all gone to look for America