Smoke and GeredrethM are the only templates I've seen on here coming surprisingly close to the one I perfected (which I permit myself to say after two years of fussing over it) - but then again your original Geredreth sprites were a big inspiration in how to create modern looking, well proportioned sprites. So if we end up with similar looking sprites in our creations, I wasn't ripping off your hard work on Smoke & GM!
The walk is fine in three frames, because we imagine the middle frames being accurate and cycling. The middle frames you added, though, aren't the walk cycle - they're the slide cycle.
Just look at the animated run cycles lying around for the missing frames - if you're making it more than three, you need the 'heel drags ground back, bent knee in background' and 'bent knee with raised foot in foreground, background heel drags back' frames. As is you're watching the foot slip backwards and forward, as typically happens with fewer frames, and of course that won't feel right.
Adding arms will certainly help the illusion so you're less likely to pick at it, though.