Sasuke's goal is world peace. From that mindset, he's going to put his powers to the use of serving that goal, just not with all the murder/mayhem. I see him operating from the shadows, contrary to Naruto operating from the light (i.e. starting a secret organization like the akatsuki, with taka at the base, but using it for the purpose of apprehending criminals, so as to prevent people like Obito or Madara from ever becoming a danger again). They both become leaders helping each other. I also don't see him living in Konoha (at least for another 20 years) or most people knowing he's at the head of this organization. Prior to 699, the people in Konoha had brains and thus are going to take issue with a mass murderer walking around the streets like its no big deal.
As for his abilities, Sasuke ought to have been a HELL OF A LOT MORE POWERFUL than what we saw on panel. Granted, he may have been exhausted from the war. Even so, Naruto is always ahead of him by a hair. 
But here's the thing, if he wants world peace and he forms a shadow organization to keep that peace...doesn't that make him like Danzo??
And actually, I agree with your idea. It would make sense for Sasuke to work in tandem with Naruto, doing things his own way. It would have been great in the manga, if Kishimoto hadn't already shot that idea down by making Danzo a villain, even after giving him a redeemable backstory.
And the Danzo-Sarutobi dynamic is repeated with Hashirama-Madara, and again with the two sons of the Sot6P. None of these were resolved successfully. And in the end, Sasuke says that one day he'll come back and they'll 'resolve' things between the two of them. So we know that in the end of the manga, there really is no satisfactory answer. I think that's why Kishimoto copped out on the ending.
Anyway, yeah it makes sense for Sasuke to be a type of Danzo character. But I think since Kishi crapped all over that storyline there's no way he could save it for Sasuke. It would have been a nice parallel though, having Sasuke succeed where generations before had failed, and having them partner for peace inside and outside of Konoha. But, nope. That's too much of a tidy ending.
Oh and yes, I agree - Sasuke should have been a lot stronger than was shown. The fight was supposed to mirror the VotE fight, which was suspenseful and gruesome. But in this last grand finale fight, it just feels like Kishimoto ran out of gas. Throwing punches and beat up faces. That's it. Sure there is the last scene of the blood where their hands used to be. But all the drama is taken out of the image because the fight is over. It's not like you look at the bloody scene and worry for the life of the one fighting.
As far as fights go, the last one was pretty disappointing.
I know how that feels. I know for my own fanfic, I am trying to figure out the best way to handle Sasuke and Naruto's power levels without having their going as insanely far as they are in the canon itself. The hardest part to me is trying to keep them from using the same powers as the Sage of Six Paths, though I am taking different approaches to Naruto and Sasuke in my fic since it is an alternate universe after all.
Yeah, it's tough. I want to show them as both enjoying the benefits of their powers, but also being burdened by it. I swear, when you start writing a fic about the end, you really realize how open and vague everything is. Kishimoto just let so much go.
Persona 5 hype 
Kishi has certainly given me a lot to clean up, which is why I'm going from 693 to 700. Honestly, I'd have to rewrite everything from the LOI arc and up if I wanted to fix most of the glaring problems I have with this series, but since the most grievous offenses are in the last eight chapters, I'll focus on those.
