For more information and community opinions, see this thread: Patch 8.1 and Cross-Faction Roleplay
For the “other addons,” it’s basically anything that interacts with guild chat (because guild chat got folded into the community system.) It’s partially broken die rolling addons (for emulating tabletop-style RPG gameplay,) transmog linkers, RP profile sharing options. I wouldn’t be surprised if it killed the ability to print DPS meters to guild chat.
But Cross RP is, for the time being, 100% broken, which is making a lot of people who enjoyed being able to actually roleplay the Alliance/Horde conflict very unhappy.