I disagree that wearing a uniform ensures an individual is treated as a professional pilot. An individual is treated as a professional pilot if the instructors are professional and not power tripping.
I can see that a uniform assists in unit cohesion and a sense of team, which are all positive when trying to clear the big hurdles that an individual faces during their training. That said, only very large schools should adopt that attitude, because again, it is down to the instructors to foster the correct training environment.
Sadly the whole argument is tainted by training organisations emblazoning their uniforms with company motto's and therefore forcing an individual to buy from them or selected outlets - often at inflated prices. Which as we know, every penny counts.
Of course it does stop the "what shall I wear today" issue for some