Other than the game being primarily PvE orientated and Conclave being basically abandoned. The main reason conclave failed (and still fails) is a simple one: Complexity.
Let's face it. Every new weapon, every new frame adds just another thing that needs to be balanced as it interacts with all the other elements. When you take the infinite complexity of mod loadouts and full frame/weapon loadouts, the whole problem grows exponentially with every new item/frame.
That of cou