If it was that way, it would be totally fine. But even heroic gear is 15 ilvl better than crafted gear!
Heroic is what's "normal" now, mythic is what's heroic now.
I agree, that tailoring will still be an option for a group of players, but if you look at the effort for one piece of 665, no one who has acces to 680 (heroic! mythic is 695) will even bother :>
imma mage, i make water, food and bags