Is there any chance it will be added in future?

I think it's a good idea (and I even would create maps for it :D)

1) I doubt that.
2) I still doubt that.

...en de wind zong van een nutteloos en verspild leven...

I know enough old farts that love SP Coop games. But for some reason it's hardly implemented anymore.

Some reasons why SP Coop isn't included in Sauerbraten:
- It actually isn't singleplayer, but multiplayer (which makes the term "SP Coop" incorrect).
- Sauerbraten isn't supporting such thing from the beginning of Cube Engine 1.
- Eihrul probably is having a way different vision as updating the Singleplayer-mode (with the exception of fighting against bots).

Is there a way? No, there isn't.

I hope that answered your questions.