@atheck
Does the power temporary or not?
If it is, then kakashi could perform that as long as obito chakra/soul/spirit still there.
Kakashi got activate AVATAR.
I'm not certain. Even if the spiritual remnants of the chakra disappears from Kakashi, some excuse could easily be made to allow him to keep it like his mind/body being embedded with the knowledge on how to use them.
The funny aspect to Kakashi's sudden achievement is the fact that he continues to spontaneously shift positions on the tier lists. From one-eyed Uchiha, to the hopeful Neo-White Fang, and now he's shifted to the complete opposite end of spectrum as the unofficial Uchiha with one of the strongest techniques in the manga. Not too long ago, people were debating whether he was still powerful enough to rival Guy, now he holds the instrument of destruction which made all of the Kages quake with fear.
By this point, Kishi's credibility has waned so much that having Sakura receiving a new power up on the spot wouldn't be too much of a surprise. She could project a gundam of her own in the form of a giant Inner Sakura like in the Ultimate Ninja series or maybe it'll be revealed to us that she's been experimenting with a very powerful genjutsu that's on-par with Tsukuyomi.