She had Carue, and she had some spinning weapon.
From what we saw about Vivi she was more a fighter than Nami or Ussop. She was more proned to go into CQC and into battle than the two others.
I think she would have keep weapons as fighting style but more CQC or mid range than Nami or Ussop. Maybe a whip or something else. I see Vivi improving to dance around an opponent and hit him. So she could have improved in agility and COO.
She would have been stronger too in sheer physical strength and physically. For her fighting style she needs endurance and stamina. So her 2 years time skip I could have seen her in a fighting island, maybe kujas, or gladiators island etc.
I see Ussop or Franky or someone else improving her weapons too to be more deadly.
About Carue I don't think she would have ditched him so she would have kept him in her fighting style. Maybe Carue would have grown stronger, faster, maybe some armor, maybe haki haha.
But all in al I don't think she would have been very strong but quite capable.