I respect your opinion, but i think i know why ralts/gardevoir isn't available in this version.
Gardevoir had the calm mind, the draining kiss and psychic, which is really a crazy combo.
Healing from draning kiss,the 90 base power psychic, and the calm mind EARLY.
I can relate that about reborn.
That can be dependable. And i disagree in that. Because most of the time in my experience, vivillion get defeated in one turn by it's weak defense and sp.def.
Gardevoir otherhand, can take a hit and survive and hit back since the sp.def and sp.atk is high.
Also the time when vivillion get's quiver dance, it's not really useful in that time too much. Only thing i can say it will be damn useful is for crawli's gym battle.
Gardevoir otherhand can be still useful and hit well i think.
However i think ralts will be available next version. Surely i guess.