If a character or idea would’ve been helpful to Marinette or made her life easier, it’ll be used to benefit Adrien in some way. (Or if it’s something that negatively affected Marinette, it’ll positively affect Adrien.)
- Kaalki would’ve enabled Marinette to escape off the train and back to Paris in “Hack-San” and thus no replacement Ladybug would be necessary and thus there would be no Adrichat shilling scene where she promises to never abandon him. (Also could’ve avoided Scarabella being nearly cataclysmed or Marinette could’ve showed up with the Horse to catch him in the act of doing so).
Meanwhile Kaalki and the use of voyage is immediately remembered in “Strike Back” to retrieve and recruit “Adrien” for the fight, and Maribug was going to use it to bring him back to Paris before Strike Back showed up anyways.
- Completely changing the name and look for a hero to pretend they’re a different person entirely/that they got replaced would’ve been SO helpful for literally ANY of the compromised temp heroes to avoid being targeted (Optygami), especially Alya (especially since she still chose to go by Rena and got only a recolor for a design change) and maybe with their safety insured Marinette would’ve potentially let them keep their miraculous instead (which would lessen the blow of the finale).
The idea however IS used for Adrien in “Kuro Neko”, but instead of doing so to deceive Shadow Moth, he’s deceiving Ladybug to keep the miraculous even after he impulsively quit.
- Risk’s powers affecting Marinette leads to her ‘making a mistake’ (that she would’ve had to be psychic to avoid) which ends up with Gabriel getting ALL the other miraculous.
Risk’s powers affecting Adrien got him to vent to Marinette about his feelings and got him to go along with the plan to switch places with Felix, keeping him in Paris completely (the trip gets cancelled anyways after Strike Back is defeated, and since Chat Noir was not needed in the fight, Adrien would’ve gotten to stay in Paris regardless even if he sat out the fight on the train).
- Su-Han and Alya’s absence in “Kuro Neko” prevent Marinette from having someone that could find a replacement for the cat instead, or at the very least call out Plagg’s blatant lies (Su-Han in particular would have), instead of having her stress out over it and be manipulated.
On the flip side, their absence means there’s nobody to find a replacement or call out Plagg’s lies, meaning there’s no one to stop Plagg’s plan to give the ring back to Adrien (since Tikki just goes along with it), meaning Adrien gets the ring back, no issue.
- Marinette is lamenting her breakup with Luka in “Gang of Secrets”, is at an emotional rock bottom, her upset is directly tied to her duties as Ladybug/Guardian and her identity. She can’t ask anyone for help without compromising herself, she directly asks for help and receives nothing from Tikki/the Kwami. Her friends then barge into her room and mess with her things, giving her no room to breathe or process.
Adrien is at an emotional low in “Glaciator 2” after a firm rejection from Ladybug, but his problems are about his heartbreak, it isn’t a problem completely hinged on his identity and it’s something that could be talked about without compromising himself/his identity as Chat. Kagami offers him help directly without him even asking for it, and unlike Marinette who’s despair was made worse by her friends trying to pry and force her to talk with little regard to her feelings, Adrien is instantly comforted by Marinette attempting to give him a gift and Gabriel calling off the akuma and bringing him home with an offer to talk about it, no invasive attempts to get him to talk are made and his feelings aren’t disregarded.
- Luka finding out Marinette’s identity in Truth would’ve not only given her a more reliable confidant than Alya, but Lukanette’s relationship would’ve stayed intact and thereby avoided a lot of the things that went wrong for Marinette throughout the season. (Truth could’ve been avoided altogether, GOS wouldn’t have happened, Sentibubbler wouldn’t have happened, etc). See this post for a full breakdown: here.
Luka finding out Adrien’s identity (along with Marinette’s) makes it so not only can Luka be used to support the square (as well as a writing excuse to keep him away since his presence would break the paper thin plots the writers present us with), but him finding out the way he did and not telling Marinette about it ONLY serves to protect Adrien (if Luka was made to divulge how he found out their identities, Chat would be painted in a bad light to Maribug, Luka keeping quiet effectively shields Adrien from consequences).
- Speaking of Luka, him specifically being in the finale would’ve probably saved the miraculous from getting taken, as well as minimizing any collateral damage from Strike Back. There’s little-to-no chance SB could absorb his Second Chance ability (especially since doing so seems to require direct contact going by the other times it absorbed any abilities) so he could reverse damage as well as be able to warn the other heroes about Strike Back. Then he would’ve immediately caught onto the fact that Flairmidable was an imposter, with how Maribug was fawning over him Luka would likely put two and two together and realize she thinks it’s Adrien when he knows it can’t be. He’d have to come clean to her about his knowledge of their identities, but that would enable them to put a stop to Felix before he pulled what he did with the Dog miraculous. Meaning Gabriel doesn’t get all the miraculous.
Luka not being present in the finale makes the fight more dire, more collateral damage happens, and with no one to call out Felix, Felix runs off, hands Gabriel all the miraculous, and gives Adrien exactly what he wants: Ladybug having him and only him to rely on, with no backup. No more having to “feel replaced” and no more sharing her with the others. He is made her “most important partner” by being made her ONLY OPTION.
This is all just from season 4, and even then I’m sure there’s ones I’ve forgotten.
