Solid Majestic Zircon (+30 sta) remains blue and Accurate Dreadstone (+10 exp/+15 sta) remains purple. Only Regal Eye of Zul (+10 dodge/+15 stamina) is green now. I can't see there any problems for tanks at all since we didn't gem for socket boni anyway. You maybe end up swapping two gems around and that's it. Worth a bunch of dailys - nothing more.
Why did you mark that thread as "tanking" when thinking about your mage? Int is the new spellpower and gems get swapped automatically - everything is fine. Caster will end up with way bigger manapool and thousands of additional hitpoints without loosing any spelldamage at all.
But yes, hunters and all the melees besides almost all DK and Rets are screwed and have to regem all their gear to agi or strength. That "news" was out for quite a while and with some research you could have easily stockpiled the required raw gems. The good news: the transmute cooldown on epic gems is gone! Grab a transmute master with some blue gems (eg: scarlet rubies) and frozen orbs (for eternal fire) in your bag.