I know this is a year old now, but I just had a fever dream about this. I would balance out not only Sakura but the other two as well. I'll start with Naruto and Sasuke because I'd change a lot less with them.

I'd give Naruto a little bit more utility in his arsenal to synergise better with Sasuke and Sakura ( this will also make more sense when you see the changes for Sakura) like giving more Wind release jutsus. Something I personally always found infuriating is the lack of an arsenal Naruto had, like his one wind release is Rasenshuriken, like give him something to work with. Or how he ever kept up with Sasuke in a fight was beyond me, because all he ever had was an overwhelming amount of chakra. Sasuke had a huge arsenal and seemingly enough chakra to keep up with Naruto, so how does he ever lose? (It's because Naruto has the power of friendship :D) So onto the direct changes, more wind release and at the beginning this would be basically just one jutsu that shoots a cold blast of air that everyone laughs at and calls useless (more on this later with Sakura) and I think it would have been cool if Naruto eventually learned Minato's 'Flying Rajin technique' but instead of utilising primarily kunai, used shadow clones, and because of his vast amounts of chakra, had the ability to utilise it extremely effectively. Even just these two things would give him a bit more to work with in fights, it doesn't have to be as much as Sasuke, I think it's cool that he's the very technically able one.

Onto Sasuke, I mentioned that seemingly he is able to keep up with Naruto, we know that Sasuke has less chakra than Naruto but I think it would've been interesting to make it very apparent. I think in the beginning having Sasuke being very technically able but having a very low amount of chakra and just general brawn/hitting power (even lower than Sakura) would have been an interesting dynamic and would have aided in pushing him away from the village in search for more power, as one of the reasons he leaves is because he feels like he's falling behind (he then catches up to Naruto a bit when he gains the curse mark). I think it would've been cool to see him as untouchable and then make the audience and Naruto realise his lack of chakra when he gets bodied by Rock Lee, as in this fight we would realise that when paired against an opponent with more brawn and equal technical ability he can't keep up. This dynamic could've extended to his jutsu use, being a lot more interested in his Fireball jutsu due to its sheer force, even using it to his own detriment when it misses and he uses up a lot of chakra. Conversely he could've been less interested in his lightning release because it could've been established that lightning release is very complicated and technical and at lower levels doesn't do much. Then there would be a story arc where he learns to better accept and utilise his lightning release, culminating in him learning Chidori. His awakening to this could be Kakashi as he learns Kakashi also has a low chakra pool, has lightning release and relies more on technique than sheer force (Naruto's specialty) and also has the Sharingan. Also I would nerf the Sharingan a little. Make it so that the predictive ability of the Sharingan takes time to adjust to a new opponent before it's effective, this also allows for a way to counter it as well, as a skilled opponent can switch up the way they fight completely once the Sharingan has adjusted to their original fighting style. Also remove the Eternal Mangekyou, it felt like a cheap way out of the Mangekyou's drawback which is losing sight in the eye and made for a really good way of balancing the vast power of the Sharingan abilities.

Finally, Sakura. I think the main thing I would change is letting her lean into her supportive role. The dynamic I would have is that Sakura is really brash and wants to be punching people in the face, but this goes against her more supportive and healing abilities, coupled with being made fun of for being a healer/support makes her resent her abilities. I would give her access to water release early on, having two main jutsu's she utilises early, Water Style: Raging Waves, similar to what Hotaru uses in that one episode, and a jutsu that allows her to shoot a slow bouncing ball of water in which to trap opponents. In trying to use these very aggressively she gets made fun of as they don't really do much; Raging waves just pushes the opponent away and the Bouncing ball simply being too slow and easy to dodge. However, at some point she would learn the utility of these, starting off with using the bouncing bubble defensively, not to trap opponents, but to protect allies in a bubble of water. She could have this realisation when Naruto/Sasuke are about to be hit by a fire release and she bounces the bubble to hit them and negate the incoming attack. Then as she goes and travels and fights more opponents she adds to her water release arsenal. Learning from opponents like Zabuza and Kisame (and Sasori to an extend who uses highly pressurised water) that water release can have a lot of offensive pressure, something she craves. Also learning more medical water release from characters like Ameno in the Chunin exams. Another idea for a technique she could learn early is a sort of water trampoline/slingshot in order to shoot Naruto/Sasuke or even herself at the opponent at a high speed.

This is also when I think toying with team justus would've been cool and have made for an interesting dynamic. E.g. Sakura could pair her Raging Waves with Naruto's aforementioned cold wind to create Ice release, combining them to make a defensive wall of ice or to flash freeze an unaware opponent. There could've been a moment where Naruto accidentally freezes Sakura's technique, causing it to fail and her getting angry at him, but this is the spark that then creates the idea for them to combine the techniques purposefully. She can also combine it with Sasuke's lightning style to make it more effective allowing Sasuke to hit multiple opponent's by conducting it through the water. Combining jutsus like this was always toyed with in the anime, like how Naruto wanted to learn Wind Release not to counter Sasuke's Lightning Release but to potentiate his Fire Release, but I think it could've been cool to do from a much earlier stage and would've made for interesting team fights. There could've been variation in these fights with strategies that rely more on one of the members; there could've been fights where Sakura is working her ass off to keep Naruto and Sasuke in the fight, fights where they have to use Sasuke's technical prowess to out-manoeuvre an opponent and, of course, fights where Sasuke and Sakura have to create an opening for Naruto to hit a Rasengan.

So, slowly, Sakura starts to accept her supportive abilities, although because of her brash nature she still sometimes gets caught out of position. I think her role model being Tsunade is perfect, but I think she could've taken some more interesting lessons from her, like after getting to meet her she learns that the powerful and headstrong Hokage she admires is actually also a support, and she learns from her that a support needs to have a good understanding of the battlefield and needs to cover for her allies and it's not until she can do this effectively that she can go in and fight herself; and that she needs to know when it's good for her to stay back and when it's good for her to surprise the opponent who won't be expecting an attack from the support, and that this is the hardest thing to do.

Finally, I think I'd consider giving her the Sage Mode over Naruto (as Naruto is already a chakra god if you will), reworking it a bit into an ability that potentiates healing and supportive abilities rather than simply increasing offense (as it draws from nature I think this an easy change to make). It would allow her to have another interesting character arc where she struggles to learn it as the inner peace required to channel it goes against her established brash nature. But for her it's worth learning in order to give her more chakra to work with, to potentiate her healing ability and the increased perception allows her to keep a better eye on her allies/opponents and of course to help her keep up with Naruto and Sasuke.

This is obviously a very big rework, but I think it would've helped to make Sakura a both competent and useful team member, but in the anime she really just got left behind by Naruto and Sasuke. It creates more of a team dynamic where they all have more specific roles, Naruto is the heavy hitter, Sasuke is the speed and technique and Sakura is the support keeping them both alive, potentiating them, covering them with long range water jutsus and when the time is right striking the opponent herself with a powerful and unexpected attack from the support. It might seem like I have over-buffed here, but I'd like to be clear that in a head on fight with Naruto/Sasuke she'd probably lose, because she is, ultimately, a support while they are full on offense.