Hi
For my own game I'm sending just very basic info like the object id, the type of object and it's location, this is enough for my client to display it (I might need to add a to that list, but having created a GameObjectSnapshot as the object and messages send across the wire, it's easy to do). If the client then needs more info, i.e. they target the object, then more information can be got at from the object ID, getting this information might be done in the background as an object enters targetting range so there is no delay when it's targetted, but the principle is the same, only give them what they need, reduces bandwidth

HTH
Endolf