Android certainly does not have lower system requirements than Windows Phone. I mean, it could run on lower spec hardware... for some definition of "run". Mine are both last-gen devices, but my Lumia has half the cores and RAM as my Galaxy and runs twice as smoothly.
I hear later versions of Android did get smoother on flagship phones, but I don't know how or if that translates to lower-end devices.
The smoothness thing is actually an architectural choice. On Windows and iOS, the multitasking subsystem will stop the world for a user gesture. On Android it treats a user gesture as one task to handle among many.
That's certainly true now, and the Android team is on record regretting the decision. It would have been the correct engineering principle for a general purpose computer but obviously fails for a consumer content consumption node.
Currently both the core team and OEMs are striving hard to work around it (reversing it would be impossible as it's baked in).
However, I think as mobile platforms increasingly take on the role of general purpose computers, it will actually end up being a net benefit, and Apple's decision will look as short-sighted as the lack of true multitasking in older Macs.
I hear later versions of Android did get smoother on flagship phones, but I don't know how or if that translates to lower-end devices.