I'm sure there are hundreds of small improvements Second Life could use, Here are five that seem like they shouldn't take more than an hour each to implement and would make our lives easier.
1. Allow About Land dialog access from the My Land and Group Land windows, remotely from anywhere you are in the world. This would allow for object control, parcel music changes, price changes, access restrictions from anywhere. This would be a huge time savings for users with large amounts of land. Also allow group land to be sorted the same way the My Land window is with name size and location.
2. Give full details on an object being paid via script in the account history report, in the same manner that objects that are purchased with the default object sale. This would allow scripted vendors to be used without having to separately store transactions with some other method, and allow lindens to back track transaction history in case of a dispute.
3. Allow debug menu changes to be retained in the same manner as preferences. Perhaps a menu selection "retain debug settings".
4. Allow bulk uploads to be canceled. Currently if you start a bulk upload the only way to stop it is to log off.
5. Stop the parcel music URL from showing up in the debug console, or at least mask it.