No, it is the passive skill being nerfed.
With the new patch, seize the Initiative, your armor is increased by 50% of your dexterity.

If you have 2000 DEX and 4000 armor, with this passive skill, you'll get 6000 armor (4000 armor + 2000 DEX).
After the patch, you will have 5000 armor (4000 armor + (2000 DEX)/2).

Perhaps it's time to upgrade STR and armor.
I have just purchased a new pants that give me additional 300+ armor.

Monk doesn't need shield.
The monster damage will be reduced too. So, I think it doesn't change the game play after all.

Barbs can do well without shield too.
You may want to look at the build without shield.