Most people in the Arma community (including me) couldn't care less.
Arma 3's main draw was always multiplayer, the editor, mods, scripting, coop, community, etc.
The campaign's a part of the base price, not a pay-for-DLC. They'll take the time to fix and improve the AI, etc. so that's fine with most of us.
Anyway, there are already single player missions in the game, along with training missions.
It's a good move, the Beta's coming along nicely, so no point keeping the rest of the game waiting while SP's being made and optimised.