Most of the Champions VGU had gain new Voice Actors. But on Irelia's case, I think this should not be done. Her Voice Actress delivers Irelia with such a strong personality. She is Irelia (specialy when she screams when using Blade Surge and Transcendence Blades). So Riot please, do not change Irelias Voice Actress on the VGU, I'm sure she will do a phenomenal work with the new voice lines! (
My blade is at your service! 
We will take the same stance we take on all our VGUs on Irelia.
If the same voice actress is available and interested and can legally audition (We don't do Union, for example) we generally let them audition.
We usually have a lot of people audition though and we will end up going with whoever performs the role best and hits the new direction/personality of the VGU. It's hard to tell if a actor or actress has enough range to hit our newer, longer scripts just based on the small amount of VO lines our older champions have. Many times the old VO actors/actresses either can't hit the range of a longer script or they just don't match the new personality/theme of the updated champion.
