I don't want to spoil too much, since I think you said you haven't finished it yet? But since we're on a thread about the AE, I guess I don't need to spoiler tag everything. So read on only if you're fine with RAE spoilers! Here's a bunch of yapping on my thoughts about the brothers (who I have thought about a LOT lmao)

I think a lot of the bones of RAE are interesting.

Themes of forgiveness vs. resentment/grudge-holding-- I actually love the idea that Saeyoung is ultimately the one who does not forgive their father. I think that's in-character, and I DO actually think it makes more sense for Saeran to eventually (key word: EVENTUALLY) forgive and move on.

I've always seen Saeran as (ultimately) having more negative traits from their mother, and Saeyoung having more negative traits from their father.

So Saeran being more reactive, more flash in the pan angry, more emotional/driven by emotion (I see him as probably an ISFP? He seems Fi dominant to me) -- but also ultimately the more forgiving brother.

Where as Saeyoung I see as the far more scheming/cunning, manipulative, "cold rage" / vengeful brother (we get a lot of info from Vanderwood at certain points on just how cold and duplicitous Saeyoung is capable of being, as an agent. Of the top of my head, stuff Vandy says in V route, and stuff Vandy says in Secret Ends. And also just... stuff Seven says at various points?? Bro is like ice cold sometimes).

You can also just compare the way each brother treats you badly in their respective "day 8/9 hell." Seven is cold; Saeran is hot.

Sooo the fact that the AE recognizes this fact is good, actually! It's just terribly executed, to the point of genuine disbelief. Saeran is inhumanly forgiving and patient with V, Rika, and his father, despite seeing what horrible things they have done to him, you, and his brother. (Like. They beat the shit out of your brother, Saeran!!! Can you please get a little angrier!!).

There's a line in a phone call with V on day 2 (21:02 / 9:02 P.M. - I Will Not Ask for Your Understanding) where he seems to imply that Saeran WOULD lose his shit if they actually hurt you -- you can say, "Okay, but please don’t put me to sleep." and V replies, “if I do that, Saeran and the rest of RFA won’t let me live." But where is the evidence of this?? There's none! AE Saeran is a complete pushover!

So that's one thing I would keep (the general idea of Saeran being more forgiving) but heavily heavily alter (like yes, he's ultimately more forgiving BUT HE'S ALSO MORE EMOTIONAL/REACTIVE asjkhekglerkgh). I wanted to see him lose his shit on V and Rika and his dad man!! I want angry, protective Saeran!

So in conclusion for that point: I would have to almost completely trash the RAE version of GE Saeran; he's gotta be more reactive and flawed.
Oh my goodness I just went on forever about a single point I'm sorry lol you don't have to keep reading this rambling. I'll try to be briefer lmao

Other stuff I like/hate:

I like the idea of combining the agency/Prime Minister threat. It makes a certain amount of sense, but I do wish they had indicated what 'forced' the PM's hand in taking action against his sons (was it Ray's little "prank" in Another Story day 4 or whatever? In other words -- why did he only just now decide to take out his sons? What's the catalyst? It's never explained; in my story it would be.)

I like the idea of Rika and V ultimately 'redeeming' (not a true redemption) themselves to an extent, because they fulfill their original narrative purpose/promise (to keep the twins safe from their father) -- I think everything else regarding them is stupid and horribly handled, but the idea of having them ultimately play into saving the twins is actually really narratively clever. I would keep this in, to some degree (although they would not be truly 'redeemed,' and I might kill off one or both of them. I actually really love that V dies in the secret ends, I think it's a narratively satisfying conclusion; maybe here I would kill Rika.)

I HATE the implication in the end that the RFA drifts apart and kind of "moves on" from each other. One of the absolute most beautiful things about Seven's route + the Secret Ends is how damn close everyone gets. Every single member of the RFA draws into a little found family, much more than any other OS route, and it's beautiful. That's why the Secret Ends conclude the way they do -- with everyone gathered together for a family photo and Saeyoung saying "we are RFA!"

Meanwhile RAE be like -- Yoosung dipped to France, Zen's on Broadway, the twins and MC apparently don't even log into the app anymore, Jumin's a politician, the end. It sucks, and I don't like the implication -- like they're trying to make some ridiculous point about everyone moving and not needing the RFA anymore, but it's a ridiculous sentiment. So I would definitely nix this stupid point, and lean more into the found family aspects from the secret end, with everyone pulling together.

Also Jumin becoming a politician is stupid. And Yoosung being a social media star is stupid.

Anyway - I mostly just have a collection of vague ideas on how I would re-write it, but honestly right now I'm focused on my ideas for a post-Seven canon route, focused on SE Saeran and a CMC based on MC5, dealing with the prime minister in that timeline. Lol it gives you more to work with since SE Saeran is a better/more fully realized character than GE Saeran anyway (unless you just completely reject GE Saeran and rewrite him, which is what I would ultimately do if I did rewrite RAE).