I think some kind of message would be helpful for non-computer people. You already have the TAB message, but I think many non-computer people, if they tried that, will just stare at the screen. They would not know what to type next.
As I mentioned in another post, we computer people think differently and take a lot for granted. Maybe this is a left-brain, right-brain thing. I don't know.
Most non-computer people I know would never guess to press the Esc key to expose the boot messages. Hence my idea to provide some basic text messages just above or below the progress bar.
I work with professionals who use computers as a basic tool. They are intelligent people but not computer people. I'm often the primary person for computer questions where ever I work. I'm no longer surprised how little people know about computers, even those folks who use them daily. For example, most people I have watched do not know the Tab key can be used to move the cursor in a dialog box. They type, stop and grab the mouse, click, type, stop and grab the mouse, etc.
In one of my past testing sessions with Zenwalk I think I saw the effect you describe with exposing the boot messages inside a frame.
Something else I liked was the Zenwalk installer scripts added an opaque graphic backdrop to provide the illusion of a graphical installer. The installer was still ncurses, but the effect was pretty good.
I realize there is a debate about who might benefit from these kinds of features. I don't see many non-computer people installing Salix or any operating system. They expect a turn-key solution with the operating system pre-installed. Most non-computer people have no interest or desire to tinker much with computers. As long as they can surf the web and fetch email they are happy.
The type of people who might install Salix or any operating system aren't going to scream much about the effects or features I recommend. However, such tweaks add a touch of professionalism that grabs a person's attention. One way to grow the Salix community is paying attention to those "little things" that make a difference and add polish.
As the old adage goes, a person gets only one chance to make a first impression. I think the same thing goes for operating systems too.