Tobi and Kisame were difficult variables when it comes to handling the Pain arc as the final saga tbh.
The final war wasn't a bad approach but it was poorly paced as everything was stuffed into a single arc. I have to say, Oda is very terrible when it comes to slow, filler-like, pacing but I don't get why Kishimoto didn't split the final war in 3 separate arcs because Kishimoto was also being terrible at pushing everything into a single thing. He brute force'd through everything.
Gintama handled its final saga, which also included a huge cosmic wide all-out war btw, in several arcs btw. Till today it's one of the best war arcs in shonen mangas imo.