There are plenty of reasons that it would be better to have Irey as Kid Flash and Wallace changed to another identity.
First off, Wallace is only Kid Flash because he was meant as a reboot of the original Wally West at a time when the original was never expected to lead the book again. His origins have always rightfully been a point of contention with Wallace and keeping him as Kid Flash only keeps him tied to that. He should be made his own character with his own identity based on that alone.
Also, now we have Wally back as The Flash for the foreseeable future and we're going to have a Wallace West simultaneously running around? Both of them are nephews of Barry Allen and the one who is now Flash was also the original Kid Flash? With them also sharing the same civilian name that becomes confusing, convoluted, and beyond ridiculous. DC sort of got away with it during the Rebirth era because they were also sabotaging Wally as much as they could but it's time to finally be dealt with. Wallace has Kid Flash doesn't fit with the current direction of Flash with Wally back in the leading role.
And yes, future versions have shown Irey depicted as Kid Flash going back as far as Chain Lightning and as recently as Doomsday Clock so there is precedence in making her Kid Flash. She also comes without all the convoluted baggage of making two Wally Wests as Flash and Kid Flash carries and having Flash training his daughter as Kid Flash would fit perfectly with the current dynamic and direction of the book. Yeah, I totally think there are more stories to be told with that in the main Flash book right now.
Keeping a character who was only made Kid Flash for synergy with a TV show that barely even uses him anyway and as a means for editorial to replace Wally because it's the leftover status quo from that era is weak. Honestly, I think giving him his own name and letting him do his own thing on the Titans is a pretty fair compromise.