I personally think that the Prison of Elders is a new mode that is similar to raids that could have a lot of potential in future updates. So far, only one game mode has been announced with no information surrounding it, but if this turns out to have a crucible-like system, I'd expect to see more ways to play in the arena coming in either future updates or limited time events similar to the salvage and ground war events in Crucible. But these are just the thoughts of one person, and we need to see what the rest of the community thinks about this, so please pick an answer and comment about why you think that way, or if you don't agree with any of my choices, state your own in the comments and be prepared to support it. We are getting good feedback and results so far, keep up the good work and arena hype.