Yeah, there was a lot of room for interesting things to happen. Instead it turned the entire war into basically flashback and verbal flashback central as we got history lessons on the historical whos who of the shinobi nations for the last 80 years. As for the filler, see, THATS why I like and loathe it so much! Like I said, its often really good and would have introduced so much awesome into the overall story if it wasnt constantly ignored, erased from memory, or just flat out never happened.