It is intentionally plain, as that is just a pass through area. One problem bringing guests to Mickey at the Judges Tent, was passing by Clarabell's desk and having people stop to take pictures. In the Town Square Theater, you are either passing through or stopping for a moment, in which case a Character Attendant should be there to interact with you. They should keep you occupied for the short time you wait there, maybe even doing a magic trick Mickey taught them.
Mickey taught the cast members magic tricks? And I've never seen anything about Clarabelle's desk, only going through Mickey's house.