Keep in mind, it will take away the discovery portion of fighting bosses. Part of what makes the Ifrit and Mog battles so fun and interesting at first is trying to figure out what their 'tells' are. (poses, the pom colors).
It's a great idea though, and I would very much like to see this implemented as the
Libra spell or ability.
As a spell, a WHM (or Arcanist) could cast it on mobs which would reveal the mobs' ability popups to the party. As in other FF games, certain boss monsters would be resistant or immune to it which would preserve the mystery and challenge when fighting them