I'm really down for each character having their own unique and PERMANENT voices. Whether or not they make new ones, it would add to originality of characters. Also, it's always best to get an interesting sounding voice, where if you heard it, you would instantly know which character if fighting.

Personally, I wouldn't mind if they went retro on the voices. For example...

Sheeva: MK3 voice (given)
Sonya: MKDA voice (originally shared with Kitana)
Kitana: MK2 voice (returned in MK Gold and I thought it sounded great)
Mileena: MKD voice (It's become part of her personality, especially the death scream)
Jade: MKA voice (I liked it for some reason, something new would be good as well)
Sindel: MKD voice (I can't imagine seeing her with a voice other than her MKD one.)

Those are the voices I feel necessary to each character. I suppose out of all of them, Sonya, Kitana, and Jade could receive new voices, but the rest need to keep their unique voices.

OH by the way, the reason why I use females only is because most of the males have the same voice and it's hard to differentiate.

Of course Cyrax is a given, as long as they don't give him his voice from MK Annihilation XD

Oh, and for the love of KESHA, I really hope that if they show a cutscene or cinematic with Goro or Kintare GROWLING, they better get a realisting sounding growl like recorded from an actual animal, not someone from the MK team going ".....rrrrrrRRRRRAAAAAAWWWWRRRRRR!!!!"
*rolls eyes*