Don't know if anyone pointed this out already but here's a look at the joint Shinobi Alliance before and after Obito says he will exterminate them all.
Before, you can see how close everyone is together. You can even see folks flak vests in the bottom middle image of Naruto.
How does everyone feel after being told that they will be exterminated? Hey guy's where'd ya go? Shouldn't we see one or two ninjas from that perspective especially in relation to the earlier image?