The delay is intentional because the skills are extremely powerful, can be used while moving, cannot be interrupted, require no MP or cast bar. That said, they are given slight delays to make up for it. You can heal 40k+ with a single cooldown or nullify all damage for 10 sec. There needs to be a downside other than cooldown. SE has stated before the cooldown isn't a bug, it's a feature and is intentionally a drawback.