You won't need to upgrade 64 items. The 6.0 systems changes will be out long before December I'm sure of it. These changes make it so set bonuses and primary stats on armor will change based on spec. Ultimately, you'll need 1 helm, 1 shoulder, 1 cloak, 1 chest, 1 bracer, 1 glove, 1 belt, 1 pants, 1 boot, 2-4 necks (depending on if guardian/feral share and if resto/balance share) 4-8 rings (same reason) 2-4 weapons, and 4-8 trinkets. It might be a little more if you want to keep the spirit from your armor for resto, but it sounds like that much spirit won't be needed after the systems changes.
So that adds up to 21-33 items to upgrade, NOT 64.
It would be foolish to ignore the systems changes knowing that 6.0 is coming out before you finish upgrading.
http://us.battle.net/wow/en/forum/topic/10703970357
I suggest you read that and adjust your item upgrade strategy accordingly.