I have only been Tanking since just before WotLK so Iím an not 100% on EH v's Avoidance, I have read a lot on this site and it has been great help and so i have been stacking EH for our progression nights and trying to build an avoidance set on the side (though i seem to have more luck with healing drops atm)
Don't worry too much about it. I wouldn't go swapping out gems and enchants for now, your stats are fine for tanking all 10 men content in game and more spread stats will come with gear upgrades.
(Btw get some new bracers, I'd say even blue tanking bracers are better then the healing ones.)
One of the things I would certainly go for though is trying to get uncritable without the use of the defense trinket. This gives you more room to use gear for the fight: need health, swap in health trinkets, need some more avoidance, swap in avoidance trinkets.
With tanking btracers, a defense enchant on your shield, and the sons of hodir rep enchant on your shoulders you can easily get enough defense that you don't need Seal of the Pantheon to reach uncrit. The Sons of Hodir enchant is really one you wanne spend you time grinding the rep on.