"git bisect visualize" is meant as a tool to pin down the culprit commit that produced a regression. Sometimes after a few steps the problematic commit is obvious, which can save some test cycles.
If you want to see the list of commits tested so far, "git bisect log" can help. To see the entire bisection state, even outside the regression window, any old "gitk foo..bar" command will do --- the bisection state is kept in bisect/* refs that show up in blue.
Can you say a little more about what you're trying to do? Is the goal to have a nice visualization of what "git bisect log" shows? (I'm not aware of any such tool, and I agree it would be a nice thing.)