I think they DO all look alike personally. I don't see these variations that people mention. The stitching on my bags appears to be uniform.
Well I notice lots of differences on my pieces which to me. Obviously the stitching will be virtually the same since they all need to be sewn together in the same areas to form the bag. I mean that there can sometimes be slight differences in length of stitches, tightness, etc.
One good example of the differences I'm referring to are with the Vernis line..some are stamped a lot deeper than others, some aren't as shiny, etc. I think you really have to take your time to examine them to see what I'm talking about.
My mom has bought LV since the early 1990's and I notice very slight differences in each and every piece she and I both have.