>>55497529zygarde has a concept that naturally lends itself to justifying new forms, though
and xerneas and yveltal aren't really designed in a way that they can just copy zygarde's gimmick the way that dialga and palkia could for giratina
like it might happen, sure, but I'm not sure what direction they could really go other than
>WHOOA IT GLOWS AND IT BECOMES EVILER/LIFIER!!!!!