Eclipse only buffs your weapons, nothing else. Roar affects weapons, abilities, DoT and double dipping all while being a buff to the entire team.
This nerf will only cause more people to switch to roar, as eclipse will die and remain an ability used strictly against eidolons or profit taker and nothing else.
Even before the nerf, eclipse's helminth damage was only a bit higher than roar's due to roar being able to just DO MORE