FWIW I spent a couple hours last night going back and forth between
split axis (with dead spots) and combined axis (with full travel), back
to back comparisons at the same track with the same vehicle. I also
should note that I'm a left foot braker, so combined axis is really
undesirable. What I found was that my best lap times did not differ
very much, but that I was much more consistent using combined axis with
left foot braking, even though that really shouldn't work. Right foot
braking with combined axis was marginally slower due to the need to get
off the gas a little earlier, but left foot braking with split axis
actually caused longer pauses due to the dead spots, and also made it
difficult to modulate the pedals smoothly, thus causing more spins and
messing up my line even when I could keep it under control. With
combined axis it was mostly just a matter of making sure I had my right
foot all the way off the gas before applying full brakes, although a
slight overlap didn't really hurt at all. In fact, there were times
when I could have sworn that the drivers were smart enough to apply the
brakes during the overlap, like they built some intelligence into the
software to make an educated guess about what you really wanted when
both pedals were applied. This was with a Logitech wheel BTW, and the
latest Wingman drivers and profiler. Driving was so much smoother with
combined, I won't go back to split axis until (unless?) I hear for
certain that the bug has been fixed. Thankfully the profiler allows me
to set combined axis only for that game while keeping split axis for all
others.