Command key changes are minor. We have a sophisticated, programmable command set configurator. This will not work. Returning to a zapped room requires typing its name in full. If partial matches worked in this case, users would end up unintentionally returning to zapped rooms every time they typed a short partial match.
Express messages are interesting.
An ignore function would be fairly easy and wouldn't even require a new table to store it in. Theoretically the ignore list could be of unlimited length but there has to be some practical limit. The short-version of the handles is a good idea and there's no reason why that can't be done. The only problem I can see is that it would transfer the entire user list to the client every time someone requests a completion. The Lobby would still serve its function as a BBS announcement board because it's the first room we encounter as we log on.