What we can see, when we look at the backside of an embroidery? Sometimes it is "messy" with threads going here and there and knots sprinkled all over. Sometimes it is almost as neat as the right side of the work and no knots anywhere. Which one is better? And is it at all relevant?
The reverse side can tell a lot about the embroidery. How are the stitches really made? Is the work done systematically or has the embroiderer jumped from one corner to another? Is there excessive use of thread where no-one can see it (waste of money!)?
But is a messy backside a flaw? If the right side is beautiful, why should we be concerned about the backside when we know that medieval people were not? Of cource, if there is too much material on the backside of the work, it can make a difference on how the embroidery appears on the finished piece.
It all comes down to one question: Which is more important factor, authenticity or craftmanship? If authenticity is more important, we should indeed try to make the backsides of our embroideries messy! If craftmanship is considered to be the more important factor, we should also take a look at the backside to give us more information of the actual work process.
Is a neat backside better? In my oppinion it doesn't matter. I try to keep the backsides of my embroideries neat, but that is just the way I like it. And judging the work by it's backside? The judging criteria include many things. The quality of the work is only one of them. And the backside of an embroidery is only one little piece of the thing called the quality of work.
So by all means take a look at the backside of an embroidery, if it is not covered. But do not judge a work by the appearance of it's backside!