That is very interesting... as far as I knew, you had actually leather, but only on the contact surface of the seat, the sides, back of the seat back (the part the rear passengers face in the rear seat), ... are "leatherette" or more accurately, vinyl with the looks of leather.
Now, I don't think it is allowed in the US to advertise something as leather when it's actually not...
That aside, I have seen a few limited Ds and I agree the leather quality is not the best of the industry, actually I've seen Kias with more sofisticated OEM leather on the seats. I think that should respond to the different leather options/qualities there are.
About the steering wheel, I have seen all car manufacturers use a different style leather for the steering wheel, a kind that is more smooth and seems harder than the soft cozy leather from the seats... I think that kind of leater is more resistant to elements like sun, sweat (from your hands), stain, etc... maybe that's why you think it's not really leather... but I would think it is.