Haha nice vid! I completely agree about Nanite-Repair. Never run without it. That being said, I don't think Mercies are completely obsolete. I see the nerfbat hitting the Fractures VERY soon. Just like every other new weapon. I imagine they will become considerably worse against infantry.
I'd rather use 20 Mercy rounds to kill someone >50 meters than 2 full mags of piss-poor accuracy AV rockets, thank you very much.