Out of habit, more than anything else, I tend to spam cure as a paladin over flash or combos when an enemy is invulnerable to attack (like the first stage ultima weapon in praetorium) as it seemed to generate enmity more reliably when I was starting out.

However, if you go and read some of the enmity potency data at places like blitzball, it kind of sounds like enmity generation is an entirely separate calculation from damage and should completely ignore damage mitigation. If that's the case, flash should be significantly better than cure, and halone combos should be even better than flash. But it really doesn't feel that way to me.