I sincerely doubt we will agree on what constitutes "Vain."
Personally, I see more "vain repetition" in improvisational evangelical/charismatic prayer ("Jesus we just...", "Lord, we just...", "And the Lord told me...", repeat meaninglessly for about 15 minutes. No less vain than my Rosary, which is 80% scripture verse, which repetition I think we both would agree is not in vain.)."
Feeling a bit sensitive today or are you just in the mood to bash evangelicals?