I'd go a step further: if you change the UI for no functional reason, you are a bad person who is causing needless consternation, confusion, and productivity loss. Even if you believe you have a functional reason, you had better think really long and hard about whether the supposed improvement you want is worth the pain of every single user needing to adapt to that change.
>I'd go a step further: if you change the UI for no functional reason, you are a bad person who is causing needless consternation, confusion, and productivity loss.