I feel like having proximity chat will in turn increase the level of immersion. Like just imagine running into some guy in the middle of a fight, he's pinned down, alone and running low on ammo. You jump in, start devising a plan, quickly dispatch of the enemy through good communication and teamwork. You both enjoy a little banter, and go your separate ways. Isn't this the basis of the game? Jump into the fray with your fellow guardians and eradicate the darkness. And hey if you don't like someone, mute them. If Destiny has the community I think it does, hopefully there will be a lot of friendly people willing to just help a comrade.