Diversity is only as good as the player pool size. Since Bungie doesn't post its current and daily player counts on each system, we can't know how healthy the Crucible is. Spread it too thin with game modes and the lag can get bad in a hurry. The matchmaking system would struggle to keep enough good ping players together. Less good choices. More players with bad internet or are just too far away from the server or you to have a stable match. I like lots of fun modes. Be careful what you wish for. Maybe lumping a few game modes into a single playlist to get an open slot for the new mode(s). Control and Clash are similar enough to put in a single playlist together. Players in the lobby could vote.