Gaiden's fault was that it sucks as a whole u can't put that one on Sasuke XD
How exactly involving team 7?
And what was wrong with the Kage summit arc?
U do realize that Kishimoto himself had plans for Sasuke. U can't blame everything on just how Sasuke is :|
The Gaiden's problems was the result of the last few chapters of the original series and Kishimoto's desire to have Sarada. The story in itself weighed heavily on Sasuke more than shin and his plans. Shin doesn't even have a connection to momoshiki like most of us expected. He was just created for the sake of sarada and her parents.
Team 7 has a track record of picking up after him regardless of what he does.
Sasuke's character in the kage summit arc and a little before was everywhere. And not in a good way. We had a regular Sasuke eventually develop a crazed persona, declare death on innocent people, abandon his team (mentally and physically), then had him go blind just so he'd take his brother's eyes.
He returns with ems, and Karin, suigetsu, and co just fall into place. Acting as the leader despite the events. Both Sasuke's apology to Kakashi and Karin lampshades his manic episodes while still staying within Sasuke's character. I find that forced.