Absolutly nothing, it takes amazing shots and never had any refused by magazines for lack or resolution etc.

...but i am a world trveler and been riding a motorcycle RTW since 2011 and always looking to go smaller and lighter. For example if I had a a6xxx series with a 16-50 lens(only for example, not a lens i would pick) the lens and sony body is smaller than the k-70 body by itself....and that about it, size matter, to me.

Just to find the right lens to go along with the body