Please give us the host/ multiplayer-option in the campaigns menu back!
This is NOT about the official campaign which will always be SP-only, but please allow us to create custom COOP-campaigns.
The host/ multiplayer-button could be greyed out or invisible for SP-campaigns to prevent any confusion, just like it was back in ArmA 2.
The current situation where your only option is to release a bunch of separate missions and call it a "campaign" just cannot substitute a real, compiled campaign, where you can have a weapon pool, mission unlocking, optional missions and other great additions that only this mode can offer.