Their argument for no multiplayer IMO is selective because if they really wanted to stay focused on what an
incredible experience this game would be they wouldn't port it to consoles.
The fact is, handling MP requires an even more systematic approach and an accounting (second guessing) of what those players will do. As Corwin mentioned on no-permanent death for party members its a way to get lazy, although if this were truly a return to the roots of Baldur's Gate they would take the time to do just that. Its one of the many things that series did quite well over say, IWD, where your party had no background stories.
Since the toolset looks to be so much like the NWN toolset I will go out on a limb and say groups like NWNX team could probably come up with something, provided the that data can be trapped and DLL's can be developed to capture them. However, it would be incredibly hacked and the base scripts probably won't accommodate MP very well.
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And this is fun, because...?
..because its challenging. After running a server with over 10000 unique accounts second guessing the complaints of my players over this sort of thing became a daily occurrence.
They were used to just dragging bodies to the nearest healer at a time when the economy was ruined and a 4th level player could get enough coin in on jaunt to the dungeon. Meanwhile the player could sit and chat in limbo until their buddy fixed them up. They could get it themselves with their other character if they wanted too. Effectively it destroyed any punishment and too many players were taking on things solo with fear of loss.
When I changed it to forcing them to lie on their back in the field of battle (waiting for a buddy) or until they got so annoyed they respawned I got hordes of complaints like that one for months.
But the same people complained month after month. They didn't leave. Meanwhile my average number of players went up. I also made combat AI even harder so it was much easier to die and nerfed a lot of uber spells in this time, took out a lot of free cash and increased the shop prices for uber goods.
Again, they not only didn't leave (but complained constantly) they almost all stopped "solo'ing" and made sure to bring buddies with them on a jaunt.
It seems counterintuitive I know but its a real paradox about game design. It can be summed up in one phrase: people want a challenge.