I speed walk/powerwalk a lot too and I too just use the "Walk" app. The interesting statistics is speed/pace, distance and pulse (and in some cases ascent), all of which you get with the "Walk" app and can see "live" with the appropriate data field(s).
I walk 16 minute miles outside and 15 minute miles on a treadmill. I use the run app because the run app reports cadence whereas the walk app doesn't. However, what I have noticed is that if I wear my VA on my left wrist, I count about 1,800 steps per mile. If I wear it on my right wrist, I get about 2,100 steps per mile. I can't really tell if it's because I use the running app.
True, but cadence disappears in Connect if you choose walk. I rarely refer to my watch after the activity is over. I don't change the wrist settings in the user profile but I doubt that would affect the number of steps it counts. I think I just have an inconsistent stride.
Based on this thread topic, I decided to try using the walk app rather than the run app. It might have been a setting on my watch but not only is cadence missing in the walk app but also I waited what seemed like forever and I never saw an HR recovery statistic like I do from the run app. I'm sticking with the run app.