Speaking personally, all I want from each of these characters -
Luffy - Plays the biggest role in both Linlin's and Kaido's defeat.
Zoro - Gets his first real battle in the New World and comes out of the island as the strongest swordsman.
Nami - Gets a proper fight which lets her test out Zeus. Has an encounter and plays a part against Linlin.
Usopp - He beats someone through his own ingenuity and resourcefulness and not dumb luck.
Sanji - Proper 1v1 against a commander level character. Raid Suit redesign is more in line with his usual style.
Chopper - Uses more of his rumble balls, proves an valued asset at all.
Robin - Her assassin/espionage skills are more highlighted and a ninja esque showdown with Fukurokuju.
Franky - Finally uses Franky Shogun and fights one of the Numbers.
Brook - Has an encounter and aids Luffy and Nami against Linlin.
Jinbe - Just. don't. die. or. leave. A fight with a commander level opponent to cement his place as a strawhat would help too.
Minks - They turn Sulong and do real damage to the opposition.
Scabbards - Kin'emon proves he is the leader of the crew by accomplishing something worthy of praise while the other Scabbards don't devolve into background noise give them a great moment confronting Orochi.
Momo - He proves his place as the true heir to the Wano Shogunate. He takes it upon himself to finally wield the Ame-No-Habakiri and proves an aid in winning the war. And please no deus ex machina where he ages and receives all the power he needs. Let him step up naturally.
Kaido/Linlin - This one is tough. A part of me wishes Oda did not bring Linlin into Wano. It only made things more complicated, imo. Kaido needs to receive more depth and focus as the antagonist, but Linlin should not be treated as an accessory to Kaido. I hope and want Oda to strike that absolutely perfect balance between them as antagonists. Similar to how he did with Teach and Sakazuki during Marineford.
Orochi - I hope his evil nature and grief are moreso highlighted over his cowardice and buffoonery. He's received a lot of focus, and I would like it not to end on a whimper.
War - It evolves from being isolated on Onigashima-to later happening across the Wano mainland. More allies show up beyond just Neko, but Izo and some Whitebeard remnants, Germa, G-5, GrandFleet. Let this feel like a real war.
Those are my general expectations and wants. I would be disappointed if any these didn't occur. I think the most likely to disappoint on my list are my War expectations and Kaido/Linlin expectations.