And this sums up the major problems most people have with Shippuden. The Deus ex Machina Kishimoto introduced at the drop of a hat, just to avoid dealing with major issues caused by the characters' actions. Take the Pain invasion you mentioned. Pain destroyed Konoha and killed thousands. It would've been so interesting if Kishimoto sought to explore the ramifications of the deaths. But no. He used a total Deus ex Machina to resolve that issue. And then there's the ending too. Why bother to pair up everyone? And some pairings don't even make sense. Sasuke and Sakura. Karui and Choji. What? The ending was very unsatisfactory. It just felt like a cheap, naive cop out because Kishimoto ran out of steam.