Tashigi has been treated and handled very poorly after the timeskip, especially in Punk Hazard where she was humiliated and a damsel in distress so many times, with her motherly moments with the kids being the only positive point for her in this arc.
On Punk Hazard I would have made her fare better against Law, to be beaten but not that easily, and to defeat Monet on her own.
I would also have made her far stronger than how Oda portrayed her, with her fighting style being developped and showcased more with her sword style being more based on speed and agility and technique compared to Zoro, as well as her being able of using observation and armament haki in a more impressive way, producing flying slash with a flower or bird style and using Geppo and Kami to enhance her speed and agility.
She would also use Kami to make her body flexible, in order for example to release herself of chains, handcuffs and of Robin's techniques, having learned from her encounter with Robin in Alabasta.
She and Zoro would also have talked more, with Zoro telling her about Kuina and his own story, as well as encouraging her to become even stronger and go after her dream, while she would come to accept that Zoro isn't evil and that he deserved his blades, while also having more and deeper interactions with Nami and other Straw Hats and a more developped friendship with Koby and Helmepp as well as Gion and Tsuru.
I would also have made Smoker and Tashigi come to Wano, with the story being very different than the gigantic mess we got of an arc, with Tashigi learning more about swords smithing and history and becoming even stronger, learning how to use either fire cutting or ice slashes, and getting in boost in haki both for observation and barrier haki while Smoker would similarly have his own power-up here. Both would have been allies again with the Straw Hats against the Beast Pirates and their allies (with the BMP being absent of the arc), and learning about the WG's dirty dealings with Kaido and Orochi here.
