Agree with both of you.
Shane's on point though in that there must be restrictions.
Even in most "standard" MMOs, lotro, ffxi, eq2 you can customize housing. Wurm of
course you can do lot's more.
The major non-technical challenge is absolutely... griefers... and that is a game design
Even a game design decision as simple as character collision can have a major impact.
If you decide to have char collision then a group or individual can block doorways, deny
access to areas etc.
A lot to consider.