It's just been announced: DOOM – Deathmatch, Private Matches & Arcade Mode Livestream

Bethesda says that they will be showing off the features live "on September 13 at 11am PT" on the Xbox Twitch channel. The free patch is due later in the month.

Here's the trailer:

My first thought based on the thread title was "is this restricted to Season Pass holders?". Now I've read the post my second thought is "man it's a shame they waited this long, especially now with the Quake announcement the chances of people coming back are pretty low". I will give it a shot but there was more than just loadouts and no weapon pickups that I took issue with in the multiplayer.