I think what you are seeing is infill bleeding into walls causing artifacts. One other thing to try is increasing the wall thickness to 1.2mm.
For the A8 I recommend trying an older (simpler) cura version 14.07 as the defaults that come in the Anet instructions work great out right of the box.
I was unable to find the download on their main site but this page has it. (make sure to scan as I can't vouch for the source)
http://domoticx.com/3d-slicer-cura-software/
I am in the process of updating to version 4.5, I will post my 4.5 slicer settings once I get it sorted(producing similar GCODE to my 14 slicer settings). Pm me if you don't see it in a week. I might even post it to ultimaker so they can update the defaults as I am sure we are not the only A8 users that have encountered this issue..
