The UI isn't final yet, so there should still be improvements to readability (floating text on a light background, etc), but unfortunately there will not be any font scaling options (see the topic
font).
Personally, I wouldn't expect an option to move the conversation UI, either (don't recall seeing anything official about that possibility one way or the other), and am not sure how that would help (wherever it is, if you are focusing on what you are reading, the characters are going to be excluded, even if they might be a little bit more in your peripheral vision than with the UI at the bottom of the screen).
