It definitely seemed like it was heading that way at one point. Though it felt like her role petered out in the novels.
Prolly a case of too little too late. Ginny had dibs and had appeared since novel 1. Then again Luna's last name is Love Good so maybe it was a distraction for the readers who were already shipping Ginny or Cho Chang.
Wonder if Ginny raised an eyebrow when Harry proposed calling their daughter "Luna", instead of Minerva or whatever.