Tadakatsu Honda's Dream, Tournament of Champions. It's Tadakatsu's party VS waves of EVERY strong warrior, including Kotaro Fuma, Nene, Sakon Shima, Kojiro Sasaki and Musashi Miyamoto. It's not very difficult, but the crowning moment of awesomeness comes when Hideyoshi and Ieyasu comes to agree he's the Strongest Warrior of Japan.
Nene's Dream, Melee at Sekigahara. Why is it so awesome? It is you, Okuni and Hideaki Kobayakawa vs Eastern Army vs Western Army. And you cut into their battle.
Nagamasa Azai is all about Love and Honor, right? But his whole story shows it is impossible to have both. At least, until... His final chapter, which is a harder version of his first chapter. In it, he decides to deal with his honor to Asakura but cleverly plotting against them, for his Honor and Love belongs to the Oda alliance. So he needs to force every Oda officer to retreat, only then to turn against Asakura and assist Nobunaga Oda in destroying the Asakura clan.
Gracia's final stage in SW3:XL, Mitsuhide who is widely believed already dead, has come out of his hiding and saves his daughter. Then, inspired by his daughter's bravery and devotion, he raised his own army which includes himself, Gracia and her three friends Kai, Nene, and Mago. Later thanks to Nene, some officers like Masanori Fukushima and HideakiKobayakawa also leave their service from Eastern army and join Akechi's ranks under the order of their "mom". Gracia also reconciled with her stubborn husband TadaokiHosokawa. Finally, both Eastern and Western army are subjugated. The land is united under Akechi banner, both Mitsunari and Ieyasu have resolved in peace and become Mitsuhide's advisers. Yup, it's a Daddy's Girl's Power of Friendship and Love which manages to end the Battle of Sekigahara in a least bloodshed result, considering both of the faction's leaders are still alive and resolved in peace. Said girl's father also become the shogun.
One of the DLC levels in Chronicles 3 is a re-telling of the story of Momotaro and the awesome factor comes from the fact that it has far more regular Mooks than any level in the game, allowing the player to rack up an insane KO count.