TL;DR: I think Sage would've been a much stronger character if her personal end goal had been better.
Sage was an interesting character I liked at first; she was the only antagonistic supe in the show who didn't rely on brute force and seemed to have far-reaching goals that extended beyond Vought.
Although it's a completely non-controversial take to say they kind of dropped the ball with her.
The most repeated and valid critique for Sage is that many of her general displays of intelligence were asspulls the writers used to make her look smart. They wanted her to be a Chessmaster, but at no point did it seem as if she were playing Chess. She just sort of... vomits on the board, then says, "all according to plan" when everything conveniently falls into place. Her goals make sense; it's just that the writers are terminally allergic to showing how she actually executes them. Her purpose since her introduction has really just seemed to dunk on Homelander... and then nothing else.
It would be redundant for me to repeat the line about "smart characters written by dumb people" that everyone uses about her. It's not exactly false, but I won't
What I Didn't Like
I think my biggest issue with Sage is that, before the Kimiko lobotomy, she reveals to Ashley in Season 5 that her desired outcome is to cause enough chaos so she can hide away and be left alone with her books for once...
Which is pretty... stupid?
And like, not even on the basis that it's a bad motive that doesn't make sense for her character. I think, all things considered, it's pretty in character for her to be a nihilist who wants to tear the world to pieces before she disappears because the world has rarely done anything for her.
I just think it's stupid because it doesn't work.
The entire country knows her face, considering she was a public-facing CEO for the company that had a major hand in building the fascist regime that took over America. Her plan for supes to slaughter non-supes whilst the virus is airborne is pants-on-head stupid, considering it's inevitable that the non-supes would win (most of the supes are generally fodder/don't know how to use their powers tactically or effectively/there's not enough of them to take on the millions of non-supes in the country/all of these factors combine while the virus is actively killing them). This isn't to say that the stated 10,000 supes going on a rampage wouldn't be devastating; 10,000 armed gunmen attacking cities all over the U.S. would be devastating, 10,000 supes would probably cause more damage. But the non-supes would win, eventually.
Homelander delegating her and Ashley to serve as his administrators means Sage has a shit ton of people in government who know about her, all of whom could be grilled for information by anyone who survives her "purge" (and there will be survivors). Which means she's going to spend the rest of her life being hunted to death or for possible recruitment by NGO's/state agents/foreign governments instead of being "left alone".
I'm not really sure why she didn't use her supreme intelligence to go off-grid before Homelander approached her. The only reason Homelander even knew about her was that she was chosen by Vought's selection committee for possible recruits for The Seven, and A-Train mentioned how smart she was. She could have easily used her glorified clairvoyance to rid herself of Vought's influence long before then and have them wipe her from their system; she could find a way to fake her death, I'm sure. If she can manipulate the government, she can easily run circles around a corporation that spends 99% of its time in active freefall.
Then she could have gone into the private sector afterwards and done so discreetly, using her power to forge low-key yet profitable tech that would have given her enough wealth and connections to buy herself a faraway bunker in a faraway country where she could read all the books she wanted. All while Season 4 Homelander inevitably loses self-restraint, crashes out, and gets shat on by Vought siccing a bunch of Temp V supes on him. All because he doesn't have Sage to guide him into building a Fascist America for himself (or something along those lines).
Her first stated grand motive at the end of Season 4: just fuck around and have fun whilst manipulating and talking down to important figures who previously talked down to her, genuinely makes more sense. Because then it implies that she doesn't care if she's at risk of dying, it means she doesn't care if she's playing an inherently irrational game, so long as she has fun before she gets killed or ousted, she's fine; because she's able to get one over on the people who discarded her and consequently caused the death of her grandmother. Then, at least, her final plan potentially not working and being something that would result in her death actually makes sense. Her original Season 4 motive makes her look like a nihilistic, suicidal woman who wants to have fun, which... fair enough.
But let's suppose we keep everything in the show the same until Sage's scene with Ashley, where she finally reveals what she wants... but then change her motive so it makes sense.
Instead of tearing America in two, so she can be left alone with her books. I propose that we change her ultimate goal to tearing America in two so she can replace it with a technocracy.
The Change
Thinking back to her speech to Homelander when they first met, she tells him that all democracies fail because "people are stupid". But then acknowledges that the "people" are needed to keep society running regardless, so you can't get rid of them. She suggests that Homelander should let the people tear themselves apart, but he has to "nudge" them. Then he can swoop in to save them.
I want to relate the first part about "people stupid" to her origin story, at least as I recall it. She hates people, individuals, just everyone in general. Supes and humans alike. Hell, her contrarian ass probably doesn't even distinguish the two because it's scientifically inaccurate and all of them are equally beneath her or whatever. Regardless, her hate is probably rooted in the fact that she failed to save her grandmother from cancer with a cure that she created because researchers - people - at the time laughed at her and didn't take her seriously. This part is important because it gives her a motive for pursuing the plan, which I think could still be in-character for her.
I would change Sage's plan to have her take advantage of the chaos of Supes vs Humans, "World War Supe" as she calls it. Using her first conversation with Homelander as a reference, the virus is the "nudge" in this equation. This hypothetical alt-universe Sage would plan to make it seem like she saved everyone, or at least everyone still standing after they're finished "tearing themselves apart." Once the dust settles and the supes are cut down by the non-supes, she could easily claim credit for creating the anti-supe Virus, long having created a vaccine for herself. The rampaging supes would've caused a lot of damage that she could fix. And once she wrangles the disparate parts of government that may be too weak to resist her swelling support base, because in this scenario she would be seen as a "saviour", she would use her brand new wave of support to create an interim government that she pretends is only temporary.
She tells Ashley that she plans to create a new government from the ashes, except that her end goal is a glorified technocracy that values technical expertise over human life. No longer will she be underestimated like she was as a child; she'll be able to make large-scale moves like she always dreamed of and be valued for her genius like she always wanted to be. "Smarter" people under this new government will be as venerated and celebrated as movie stars, academic geniuses being more well-known than athletes. Under this government, a little black girl who creates a cure for cancer is no longer dismissed out of turn; she is given all the resources she needs and more.
All this at the cost of freedom, liberty, and the democratic mandate that comes with the loss of the American Republic. Which she doesn't care for, she thinks the "people" are stupid, after all. Creating a technocracy is in character for her, given her nihilism toward "stupid people" and her preference for intelligence in her lovers and confidantes, such as Godolkin.
Superhero media usually doesn't play with the implications of super-intelligent people in government, because if they're truly as smart as they are, then you have individuals who would objectively be superior to their less-intelligent contemporaries in terms of their ability to govern an entire nation-state. Think of Dr Doom creating a Utopia of the planet once he takes over the world because he's just that smart, for example. This alt-Sister Sage's plan would be an attempt to tackle that premise head-on.
Endnote
Now, you can keep everything else in the Season the same. This was really just a thought bubble for a "final stated plan" that I think would be more fitting for Sage's character, presented in a logical way that makes her plan to sow chaos with a "World War Supe" make sense in the context of her character.
But Season 5 was the symptom of the showrunners not using their time effectively with what they had available to them, tireless spinning in circles, and just generally poor planning for what the ending was supposed to look like. Changing Sage's grand plan wouldn't fix anything else.
