@Fallen:
Forced? Maybe.
Zabuza and Haku are brought back to life with a broken jutsu, despite the fact that Kabuto would have no way of knowing where they were buried, nor would he likely have any interest in them considering their strength. The entire zombie thing is forced as hell.
Unnecessary to bring them back? Eh, kind of. However, having them back is a nostalgic treat (regardless of how much a cop-out a resurrection is).
I enjoy nostalgia as much as the next guy, but it's all about execution. For instance, I actually did kinda like those two nods to the bridge arc with Suigetsu taking Zabuza's sword, as well as the return of Inari and the old guy. But literally resurrecting Zabuza and Haku for a completely unnecessary battle for the war arc is just an unnecessary raping of a far superior arc.
Do not get me wrong; I am not about to ride the waves of nostalgia to make my opinion biased, but I know that I and perhaps others felt there was more to Zabuza and Haku and felt that some things were left unanswered (or atleast a few "what-if's" about which some may be curious). More info on the two probably was not enough reason to bring them back, but it was nice to get since they were coming back through Impure World Resurrection anyhow.
Not really. Everything that needed to be said about Zabuza and Haku was said back in the bridge arc. I'd like to know what more you would've liked to know about them. And your argument kinda falls apart since the last few chapters haven't really told us anything new about them.
Mostly, the Seven Swordsmen of the Mist really needed some clarity and background, considering how much their reputation has been prevalent throughout the story.
I kinda would've liked to see an arc centered around them. Or, heck, maybe it could've been a gradual thing. But no, Kishi blew it (as usual).