Do you have any logs or anything to back this up? Because i've reforged out of the expertise cap before and didn't really like it if i'm honest. Plus its the biggest dps increase if you reach the hard cap, seeing as quite a few of the heroic fights have a tight enrage timers, plus i like ranking #1 on fights on WoL
But yeah honestly i'm having no problem with damage unless i forget to use my CD properly or just the fight hits really hard anyway in which case there's not a lot i can change seeing as my other tank is taking a lot of damage too. With the recent guard fix my healing on WoL has gone up quite a bit (was beating our blood DK) and when you manage things properly i'm usually the easiest tank to heal.