Well reality speaking, I think her minigun should be better against squishies and her rockets better against tanks.
I am not sure if this is how Riot has it/I haven't played Jinx neither know 100% about her abilities.
But I would have attack speed on her minigun which would be less effective against tanks and armor penetration on her rockets, making it more effective against tanks.
Now game-balance wise, I feel that her power is fine as it is/she doesn't need buffing. I would most likely consider a slight nerf for her, like they did with Vayne.