Yes, it has to be done in a such way that if I want to read slowly, then the screen is not automatically scrolled.
I believe such mechanism is right now implemented in Battle Log window. If you scroll to the bottom, then Log is automatically scrolled as new events occur. However, if you scroll up a bit then the log stays in the fixed position and you are able to analyze past events at your own pace.
As far as the look of the window is concerned, I don't see anything wrong about the regular conversation window, as long as it behaves as I described. I feel it gives better immersion than the journal.
