Not really a necessary feature since we have surnames. On the other hand I guess there isn't really a reason to not have this feature either.

Keep in mind though that even if there was a system to free up names it doesn't mean the names you wish to have would become available. That level 1 inactive character may be an alt of someone who plays every day. Also in a game where people sub just to keep a house they have no use for, players who want to reserve names would simply fulfil any new requirements in order to do so.