The skill level is not related in anyway with the ability of one to make productive unbiased balance comment.
Trying to find criteria, which one has to fulfill before proving helpful balance comments is practically pointless because even if one could come up with such criteria, one would than have to enforce a way to separate people into categories.
It is actually much simpler and far more productive to focus on the comment themselves instead of focusing on the person who makes the comments.
The hostility and toxicity with which some people respond to posts, is indicator that they have personal issues and they are far less productive than the people who made the original post.
I'm not talking about average players who understand stats and balance.
I'm talking about the very bad players who do not understand it, but will post about it anyway.
Having skill to use units to full extend helps tremendously and not having it, especially when sticking to just one faction/side means to very biased opening posts.