A 'problem' with some coop board games is that it's easy for a dominant person or people to take over all decision making in the game.
I personally see this happen in Pandemic all the time, even though it tacitly tries to prevent this.
I can only think of three techniques.
Hidden information. Each player has information only they can see, so all players can be involved as information sources.
As a side note, as far as I have seen this is not very effective, it's usually very easy to get all the 'pertininent' information quickly and move onto decision making
Timed turns The players have a limited amount of time to make their decisions, and there are more decisions to make than one person can make, or more information to analyse than one person can consume.
- XCOM - The Board Game
- Space Alert
Distrust Players cannot trust the information other players give, so they must make their own choices.
- Shadows over Camelot
- The Resistance
This type predominantly uses a traitor or potential traitor to cause the distrust. Perhaps there are other games that use a different mechanic such as forcing players to lie about certain things etc?