Just a few comments on your new UI design <http://i.imgur.com/415Y1.png>:

== Suggestion 1 ==

It seems, from your screenshot, that you plan to hide the [ Next > ]
and [ Cancel ] buttons, and show your [ Yes ] and [ No ] buttons
instead.  This is doing something completely unexpected to the user.
I've used hundreds or thousands of Windows installers and IIRC never
seen such a thing.

Instead, may I suggest a checkbox:

    [x] Prepend the Python folder to the PATH environment variable (recommended)

and leaving the [ Next > ] and [ Cancel ] buttons as-is.

== Suggestion 2 ==

Better yet, get rid of the screen which talks about changing the PATH
entirely.  Instead, on the feature-selection screen, make the
prepend-Python-to-PATH option be selected by default.

Why not try implementing this suggestion in the next 3.3.0 beta?  Then
you can see if the tech-support burden increases or decreases.