I do understand this is not possible right now, espeially given there are only 5 companions available in single-player mode at the moment. But I do hope that as Larian adds more companions to the roster, the party size in later EA versions (or even just the completed game) can be bumped up to 5 or 6 members. Even if this is not implemented in multi-player mode, or even if it is left as an option that can be chosen at the start of the campaign.
With the player created character and the five companions they actually have a full party of six ready to go, but I would prefer that they focus on finishing and balancing the game for now and add the option closer to a full release.
