Nerfs got nothing to do with it, restoring your own arm and instead relying on a fake(inferior quality) arm he wpuld do if possible. Considering he did the same for Kakashi without him even asking for it. The only thing that makes sense is he can't do it anymore.
Yet he was able to took the ball of light out of Hinata without harming her.
Yes, its pretty relevant сuz it proves that he still has his power and he didnt restore his arm only because of nerf.
Not really since we dont know how or what he did or if it's relegated to 6psm powers.
Nah, I don't troll (often), but as they said below, not only he regenerated an eye out of nothing (a feat well beyond any regular medic), he also stopped the 8th gate from killing Gai, plus with Kurama's chakra to the whole army IIRC besides empowering them that also healed them as well (as it healed Gai and Kakashi when he first got into bijuu mode).
