With the new (community-inspired) emphasis on the non-roguelike aspect, there will be full parties. You will start as an individual and recruit whatever party members you want (you also won't be penalized for flying solo - maybe going solo gets you experience faster?). Edit: you can manually control your additional party members or have AI control them, whatever you prefer.
In roguelike mode, probably no parties although perhaps you can recruit AI controlled NPCs. Again, this is just to make low resistance to starting a new game, and low investment in your current game.
Parties are confirmed, and the dynamics of such are now fully up for debate. Gentlemen, let us begin. Some starter questions to consider:
- Should there be a maximum size for parties?
- How easy should it be to gain new party members?
- What should define the ease of which you get someone to join?
- Do NPCs have parties? If so, can you join?
- If you join an NPC's party, or they join yours, what keeps you or them from wandering away from the group and getting lost?
- Is it possible for NPCs to leave your party at will? What would be the catalyst behind this? What keeps NPCs from splitting away from your party all the time?
- What measures (if any) should be taken to encourage the player to have parties composed of members with differing skillsets?
- Would party members be able to choose what skills they level up for themselves, or would you have the ability to choose for them?
- Do they take care of their own needs and wants? Are they able to use money to buy their own weapons and armor?
- How is loot split between party members? How is money split?
- What keeps them from leaving your party and stealing the artifact sword you worked so hard to get? Should it be possible for them to get the artifact sword if they desire it badly enough?
- How should experience be split among party members? Is it based on whoever lands the last hit, or something else?
- What keeps other party members from suddenly turning on you? Should this be permitted? Should you be able to attack other party members?
- How should micromanagement be handled?
- Should players that micromanage have an advantage over those who don't? How do you find balance between the two?
Just a few ideas to think over and discuss. edit: Fixed a typo.