Why every list change idea is terrible (as simple as possible)

[Castle2.0]

Still haven't read a good argument as to why taking some measure to throttle account sharing would be bad.

Because the mechanisms offered so far wouldn't stop the small group of elite /listers and it would have negative impact on at least some casuals.

limiting account sharing would be a fix

What exact mechanism should be used to limit account sharing? So far we've heard IP cannot change - but VPN or shared VM (don't even need to log out of the character on this one.) VPN much more likely and accessible to even the brain dead.

Anything else?

I'm all for limiting account sharing, but I can't see how it would be done well.