And I'd really like to see a CF where social play is more encouraged, especially at lower levels. I don't want the ability to solo rank to go away, exactly, but I believe the benefits of solo ranking should be far outstripped by those gained by interacting with another PC.

A few ideas off the top of my head:

Low level quests should be group solvable, including the kill X things in a way that doesn't make it impossible to complete any/all you want.

Practicing skills vs. another PC should be clearly better than mashing on mobs for long periods of time. This may require putting something like Parynthian boxing gloves (that's a wayback reference) back into the game, but in a way that doesn't allow PC vs NPC to work.

Some way to offset skill learning rates in a group vs. solo. Maybe you can learn defenses by watching a groupmate defend? I don't know exactly. Or invokers can learn shields if a groupmate is getting hit and has shields on them. Things along that vein.

Something that allows more audience members (see video) to participate in CF without feeling totally overshadowed by the "players" or isolated from everyone because they want to enjoy
the game more passively (by being the "third") instead of being Rambo.

Just some random thoughts.