I've mentioned this in a few other threads, but it's probably worth repeating here as Repose going to the Role Actions caught my eye too.

Repose was actually pretty meta during the ARR beta, it was pretty standard fare to CC all bar one mob in a pull and single target things down. WoW went through a similar phase with it's dungeons too.

Now I'm not suggesting that this should become the norm again as it's not particularly conductive to flowing gameplay, but as you suggest, I think it's an idea that could be revisited. A really simple way to add value to it without any significant mechanical changes would be to give certain mobs a pet. Sleep the pet and have it despawn when the owner gets killed. Couple that with making the pets either particularly dangerous or annoying to deal with and you've got instant value.

Here's hoping this isn't a missed opportunity by SE.