Sage and Jon from bungie already stated why they made the change. They both went on to say that the main reason for them giving a shorter time limit go symbiote was because it was literally the only thing gunslingers used. They wanted to provide the game with more choices rather than having ONE clear choice for pvp. Before you say "why can't they let me play the way I want" sage also addressed this, and said it is because we want all players to play how they want that the change was made, so not ONE armor or piece dominates the subclass. This was from crucible radio on planet destiny for those that want to check it out