The biggest problem with it being based off feedback from whiny players, is simply that the patch has been done for FAR too long, to be based on such things (as in, this patch has been done by at least the beginning of October, before the US 3DS version even came out)
And to my understanding, the Japanese community has much different views than some whiny US players do.
TL;DR: Its more than likely not based on whining of any kind, merely Nintendo thinking certain people were too strong
Thats not to say I agree with Mac's aerial side B getting nerfed (no, he didn't need that, the jab nerf was definitely needed though; the only other person in the game who can do 20% with a jab combo is Shulk, in hyper buster mode which only lasts for 6 seconds, and has a 10 second cooldown after it ends)
The only other nerf he got besides the aerial side B thing, was his jab.