I was trying to think of ways for other characters in our family to be part of your adventure in some way, when I first heard of tagging way back when, it put me in mind of the tag in-tag out feature in Marvel vs Capcom. 

I do think it's a shame that my characters will never be in the same place at the same time, never cross paths and never interact.

I was thinking about how this could be incorporated, and the two ideas I brainstormed were:

Having them stationed at your residence similar to how maids and pets pop up to greet you. People may have 20 or so alts at this point, so the number of visible characters would probably need to be restricted based on the size of the property.

The second idea came from the first, and it was to have the option to bring along Family members in place of pets and serve a similar function, so your player character is flanked by a couple of companions on your travels. These shouldn't be visible to other players it would probably brick the game. 

How you'd accomplish pulling across beauty album values, outfits and saved dyes in this manner is impossible for me to say and I'd be inclined to think it wouldn't work, but if there's a way to register a 'lite' duplicate of your character with a couple of idle animations, and they can accompany you in a similar way to pets with less janky movements, I thought that would be really cool.

The world of bdo can feel a bit lonely for a character at times even when you're in a guild or doing party content, as we're all solo characters coming together, but this may give a different flavour to your own character and make them feel like they have their own people, people waiting for them at home.

You could even give them occasional stock speech bubbles to pop up when idea for a while, saying something like "I'm in the mood for an adventure today" or "where are we headed?"

Writing this has reminded me of a smaller change I'd like to see: can we PLEASE individually show and hide pets so we can have all of them active but between 1-5 visible? Some may be particularly happy with one companion pet, but they may not want to have a cluster of wildlife jumbled up and scattered around them at all times. I have mine hidden at all times but I'd quite like to see one of them.

So hands up, who'd love for other members of their family to be around to say hello to / or to help you collect loot and who'd like to have one or two of their favourite pets visible? 

- Inactive family members as node workers.

- Inactive family members doing fully-AFK things like fishing, combat training, horse training, others?

And you could see them at their work/AFK, or wherever they are parked.  Limit so you can only see your own.  The world can still interact with them, so don't park with mobs unless you want to leave a corpse lying around.

Servers grind to a halt.