I don't see how it would've made that big a difference.
Voyager's problems lied in writing, not the gender of the Captain.
We've had numerous Trek actors play different roles. She actually doesn't hold the record for that.
The number of times in the latter shows I caught myself thinking:
"Hey, that Hirogen is Martok!" "Hey, that 22nd century Klingon lawyer is also Martok!"
"Look, cardassian Tebok!" "Oh, here's blue Weyoun!"
But I usually considered it a good thing. Hertzler, Combs, Alaimo and most of the recurring actors were very good.