Google Talk is designed to be simple and fast, and for that reason I love Google Talk. Even then I would like to see some more basic features added to Gtalk, which is required to keep my privacy of online status. if I want to hide my status from my contacts, there is no option other than signing off the messenger. Gtalk has a block feature, which completely removes the contact from your Google talk list and you will have to manually unblock from the Settings.
Invisible Mode: Sometimes I prefer to login as invisible to everyone. I just want to be online and hide my status from friends especially when I have a lot of work to do. Even though I am busy with work, I still may want to chat with my wife!
Stealth settings: I also would need to selectively hide or show my online status from a specific friend or a group of friends. For example, I during working hours, I want to be seen online to my colleagues across the world while offline to my personal friends. When at home, I want to be offline to colleagues and online to friends.
Groups or Labels for Friends List: Google Talk does not allow me to group my contacts together and broadcast send a message. The grouping could be done by applying tags/labels to contacts.