Modern and ancient word choice: 昔人 vs 古人 vs 前妻
never? you're kidding :) the term "古人" is also used in poem.

just a casual search: 

in 通典·卷三十二 (end of p73, and start of 74):


  賦詩曰
  
  古人云此水﹒一飲重千金
  
  若使夷齊飲﹒終當不易心


next, 杜工部﹒ 吾宗


  吾宗老孫子﹒質朴古人風﹒耕鑿安時論﹒衣冠與世同
  
  在家常早起﹒憂國願年豐﹒語及君臣際﹒經書滿腹中


later, 孟宗獻 wrote


  古人借宅亦種竹﹒大是饕竒心未足﹒髙齋聞有萬琅玕﹒坐對懐山飲秋緑﹒
  
  官閒勝日無一事﹒尊酒不空仍有肉﹒他時剥啄叩君門﹒髙枕矮床容我宿


imo, characters are like fashion, "trendy" today, would out-of-date".

have fun :)