I know. I hate how he pushed aside other Akatsuki members. They had so much potential. Especially Kakuzu and Sasori.
I've always thought about it and I would make only 2 changes to the Naruto manga and they're both about the Akatsuki.
1. Kakazu, Sasori & Deidara all survived their battles and survived til the end with Obito & Zetsu. They realise that after Pain's death, Tobi is not who he says he is and they realise they are being used. The three team up to form a coup d'état but end up being defeated by 'Madara'. They go rogue and surprise attack during the final battle.
2. Itachi & Kisame both go rogue during the timeskip. This makes Itachi more mysterious and gives a massive hint to the whole 'not actually evil' reveal, the other Akatsuki are hunting them, this would make both of them more likeable, less OP and have more depth. They'd also be out of the picture for most of Shippuden.
But no, Kishimoto introduces all these amazing ninja with all these abilities and kills them all off for fun. He suddenly realises that these 2 random akatsuki members (itachi & tobi) will be the only ones worth a damn and forgets that the others guys even happened. All of the Akatsuki had so much more potential.