Not quoting all of it, but:
1)One does not simply integrate advanced techniques with swordplay.
Kakashi designed the Chidori, a nature and shape manipulation technique, at the age of 13, after trying to add nature manipulation to the Rasengan and failing. It took him another 18 years to figure out how to use it with a kunai. Even Sasuke, with all the resources of Orochimaru's establishment at his disposal, took multiple years to figure it out, and he was being tutored by an S-class shinobi sword user.
2) Rasengan is a weapon, not a chakra control exercise. You need chakra control to pull it off, not the other way round.
Naruto only managed to pull it off with the tutelage of an S-class shinobi, and the profligate use of more chakra than most jounin routinely expend in a battle to hack the technique. You'll note how no one else can afford to expend multiple Shadow Clones for 1 move as a routine maneuver.
3)Notoriety? Dude, the type of people you use A-rank techniques on are the most likely to survive them. Remember Kabuto?
Do not fool yourself that you can control who gets to see you use a technique, else Minato the speedster would never have gotten a reputation.
4)Hisana is a Wind Release user.
There are literally tons of Wind Release techniques out there that would serve as "powerful holdout weapons", up to and including the sealless A-rank Blade of Wind Baki used to impale Hayate Gekko. The idea that you need the Rasengan for this doesn't really have any supporting evidence.
Similarly, Hisana has medic-nin training.
Between general ninjutsu, elemental ninjutsu, genjutsu and medical ninjutsu, Hisana has more than enough methods to hone her control.
That has never been an issue.
When we have native A-rank control, and if the opportunity comes around? If it's not too much trouble, maybe.
At the moment, it's a waste of time and effort more productively spent elsewhere.
For example, we're an Uchiha sword user with D-rank genjutsu. That's just sad.