What's going to happen once the changes take place, is when a few people are going to find the next "big thing" as far as weapons are concerned. Praise it to hell and back and watch the playerbase bandwagon the crap out of it.
Bungie will take notice and nerf it eventually. And the cycle continues.
Gjallahorn was broken mainly because no other rocketlauncer could match the kind of damage + utility it does. Thus, it became the bandwagon (sadly mandatory for bad groups) whereas other RL were considered unusable by the community who don't know any better.
Truth, Dragon's Breath, and Hunger should of had something more unique to make them just as attractive. Wolfpack creates a second rocket in the form of tracking clusters... which made it perfect for Crota and Atheon. Dragon's Breath, the little fireball should of been made to stick to the target and cause damage overtime for a few seconds. The Truth should allow a 1-2 second stun on contact, allowing other players to focus fire. Hunger of Crota's little clusters could act similar to wolfpack rounds but do smaller damage.
Each suggestion there would of given each RL some kind of uniqueness to it, and valuable just as much as Gjallahorn. It's a shame the dev team probably didn't consider that.