It depends. I personally believe that much more of the blame for Azula's upbringing should be given to Ozai, rather than Ursa (though she was far from a perfect mother regardless). If Ozai's influence had been lessened, Azula likely would have benefited from a better relationship with Ursa-- but if Ozai's presence was a strong as ever and Azula still enthusiastically followed in his footsteps, Ursa probably wouldn't have been able to affect her daughter much at all, no matter what she did.