We should make this a BG3 ideas and requests thread for all.
For me, I want it to have some of the same features that gave NWN1 and NWN2 the longevity they had and still have. Players are still making content for both, despite support ending years ago. What made those two games last as long as they did was the toolset and ability to direct connect to servers via IP address. Meaning that even after the Gamespy matchmaking servers went down people could still do multiplayer. So for me the three main things are as follows:
Toolset
DM mode
Private hosting(direct connect to IP)