I see what you are getting at.
I think for me there are a few factors on the new animation that make it less of a walk compared to the Megaman animation. I think a lot has to do with knee definition and angle.
Megaman has a defined knee bend on the front leg to suggest the character to running forward where the front leg on the new character just seems more straight. Megaman's back knee/boot top is lower than the rest of his back boot, but for the new character, the top of the back boot appears to be in line with the boot toe (where the toe is higher for Megaman suggesting more of a bent knee).
I think another difference is that Megaman's back leg, with its full knee/thigh area works better than the skinny thigh/knee to boot transition on the new character where to me the back leg almost looks warped/broken as opposed to bent at the knee.
It is possible that the size difference (Megaman being shorter) could play a role in the leg movement too.
Finally, the new character's arm covers up some of the back leg, but Megaman's animation does not. Perhaps this plays a role too?
I hope none of these comments come across as harsh. I am just trying to explain why perhaps the new animation feels less like a run to me.
I redrew one of the new characters with 8 frames which works much better for me anyways, allowing for a smoother transition as only having 4 makes it more challenging I think. Also, this Megaman sprite may be a classic, but I don't find the run cycle to be the best anyways (at least visually for me when I view it).
Perhaps this is different to when the sprite is actually in motion as I was only viewing the frames in a still position.
All the best!